Hi Bjmwsons,
Just in case you haven’t read it yet … the first place I would start your research is the tutorial post here which includes the basic information, steps, and guidelines that can help you make the best choices. It also includes a list of some of the manufacturing members of the site that sell latex mattresses or latex hybrids with a wide range of options, designs, features and return or exchange policies that are among the best quality/value in the industry.
Plushbeds uses good quality materials in their mattresses and are certainly better value than most of the mainstream choices in the industry (and they advertise heavily on the internet so many people come across them) but I would make some careful comparisons with some of the other choices that are available to the members here based on the criteria of your personal value equation that are most important to you because you have some of the best options in the industry to choose from. A forum search on Plushbeds (you can just click this) will bring up more information and feedback about them.
While a Dunlop core and a Talalay comfort layer is a popular combination … different people may have different preferences and both the Talalay and the Dunlop manufacturing methods can produce high quality latex that can be used in any layer of a mattress. There is more about the different types and blends of latex in this article and in post #6 here and there is more about the difference in “feel” between Dunlop and Talalay in post #7 here but the most effective way to know which combination you may prefer is with your own personal testing or experience.
If you are dealing with a reputable company then the “risk” of buying online will depend on the options they have available and how well your initial choice matches your specific needs and preferences in terms of PPP along with the options you have available after a purchase to either re-arrange or exchange layers or to return the mattress itself and any costs involved.
There are too many unknowns, variables, and personal preferences involved to use “theory at a distance” or other people suggestions to choose a mattress (see mattress firmness/comfort levels in post #2 here). If you can’t test a mattress in person for PPP then the best way to choose which one is best for you would be with more detailed conversations with the manufacturer. They will know more about their mattresses than anyone else and are in the best position to help you choose which of their mattresses has the highest chance of success based on the “averages” of their customers and the information you provide them on the phone.
If it also has good center support to the floor and your beframe is strong enough to support the weight of a latex mattress and the people that are sleeping on it then it would probably be fine in terms of support and you wouldn’t need a foundation but a solid support surface would also be an additional risk factor in terms of ventilation and airflow under the mattress (see post #10 here).
Latex is the most flexible of all the foam materials and it is normally an ideal choice for an adjustable bed. There is more about choosing an adjustable bed in post #3 here and the adjustable bed thread it links to.
Phoenix