Hi jleb,
Welcome to the Mattress Forum! all the way from down under 
Hopefully I can help to clarify some of your concerns and provide some information that can help answer your questions.
First some of the âbasicsâ âŚ
Just in case you havenât read it yet ⌠I would make sure that youâve read the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that you will need to make the best possible choice.
When you are in higher weight ranges then it would be more likely that you will need firmer materials than average, possibly a thicker mattress (depending on the specifics of the mattress), and you would need to put a greater emphasis on more durable materials as well. Post #3 here also has more information that would be helpful for those with larger or heavier body types.
The focus of the site is on the North American market and Iâm not familiar with the Australian market but the materials the manufacturers there use are the same as North America and Europe. Outside of PPP (Posture and alignment, Pressure relief, and Personal preferences. the most important part of the âvalueâ of a mattress purchase is its construction and the quality/durability of the materials inside it regardless of the name of the manufacturer on the label. Post #2 here also includes links to most of the forum threads from Australia (Iâve added your topic to the list as well) and post #7 here includes a list of many Australian manufacturers and retailers and a few comments about some of them as well that will hopefully be helpful.
There is more about the most important parts of the âvalueâ of a mattress purchase in post #13 here that can help you make more meaningful comparisons between mattresses.
The price of a mattress isnât necessarily indicative of the quality or durability of the materials and components inside it. You will often find a broad range of prices for mattresses between manufacturers and retailers that use very similar materials
Both of these mattresses use 100% natural Dunlop latex so in terms of the quality and durability of the materials they would be closely comparable. I would also keep in mind that first and foremost a mattress is a utilitarian purchase that has two main functions which is to keep your joints and back in good alignment and to relieve pressure in all your sleeping positions. Everything else is primarily a preference.
You can also read about some of the properties of âyour perfect mattressâ in post #2 here. A mattress is not supposed to âwowâ you but to âdisappearâ underneath you so that you can sleep in good alignment, without pressure points, with good temperature and moisture regulation, and without restricting movement when you change position along with other preferences that are important to you. These are what lead to healthy sleep because when you are asleep you canât feel the âwowâ ⌠and what your body needs to for deeper more healthy sleep is what is most important.
Comfort or âshowroom feelâ is very subjective and relative to the person and choosing the most suitable mattress based on comfort alone has less than even odds of choosing a suitable mattress (hopefully you read the study I linked earlier). This would be much like choosing foods based on taste alone regardless of their nutritional content so I would make sure that you test a mattress using the testing guidelines in the tutorial.
There is more about organic latex in post #6 here and more about organic certifications in post #2 here and the posts it links to but from a performance and durability perspective there is little to no difference between 100% natural Dunlop latex that is certified organic and 100% natural Dunlop latex that isnât outside of the certification itself and the additional costs that it adds to the material. Of course choosing certified organic materials can still be a personal preference or a lifestyle choice that can be important for some people and there are some ânon performanceâ benefits that are part of the organic certification process as well (see post #3 here).
âProgressive feel technologyâ just means that the layers of latex become progressively softer from the bottom to the top of the mattress.
Powerfoam Industries manufactures âfinished sleep systemsâ and donât manufacture the actual latex itself although itâs possible that they may also be a distributor for latex made by a different company.
Most of the focus on this site is on North American manufacturers so there isnât nearly as much mention about manufacturers that are outside of North America but a forum search on naturatex (you can just click the link) will bring up some comments and feedback about them.
I would be very cautious about using other peopleâs experiences or reviews on a mattress though (either positive or negative) as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you and in many cases they can be more misleading than helpful because a mattress that would be a perfect choice for one person may be completely unsuitable for someone else to sleep on (see post #13 here).
A different mattress cover or quilting layers can certainly affect the feel and performance of a mattress so it would certainly be a valid concern if you decide to choose a mattress that is different from the one you tested. There is more about quilted vs unquilted mattress covers in post #12 here and the posts it links to.
There is also more information in post #2 here about the different ways to choose a mattress (either locally or online) that is the best âmatchâ for you in terms of PPP that can help you assess and minimize the risks of making a choice that doesnât turn out as well as you hoped for that are involved in each of them and when you are considering a mattress that you havenât tested in person then the return/exchange policy would generally become a more important part of the âvalueâ of a mattress purchase.
I would be very cautious about choosing a mattress that is too soft for your higher weight range as well because it can certainly be more risky in terms of alignment issues and I would make sure that you did some very careful testing (hopefully using the testing guidelines in the tutorial) to make sure that you arenât being unduly influenced by how âluxuriousâ a mattress feels or the âwowâ factor and that the mattress really is a good âmatchâ for you in terms of PPP.
Again itâs not unusual that a manufacturer outside of North America isnât mentioned on the site although a forum search on latexmattresswarehouse or an exact term site search on latex mattress warehouse (you can just click both links) will also bring up some comments and feedback about them as well.
As youâve read they are certainly not the only supplier of mattresses that use certified organic latex.
Unfortunately this is something that only you can answer based on your own sleeping experience but if youâve done some careful testing on latex mattresses and you like how they feel and perform in a showroom then the odds are much higher high that you will do well with it when you sleep on it as well. There is also more information about dust mites and allergies in post #2 here that may also be useful.
Phoenix