Hi tommyboy,
That’s difficult to know until you have tested them but the memory foam uses good quality materials that would be suitable for your weight in terms of durability and is on the firm side.
They have two latex models, both two sided, one of which is thinner (firmer) and the other thicker (same core but additional softer comfort layers on both sides). They would also be worth testing and latex is a good quality material but they use a 32 ILD base which may be a bit on the soft side for you and the one with the extra comfort layers uses fairly soft latex as well although it’s not too thick. They also display them on a box spring (which has flex) rather than a foundation (with no flex) which is somewhat unusual for a latex mattress so if you do test these I would make sure you test them without the box spring on a firm foundation as well (or one of their adjustable beds which also has a firm non flexing surface) to see if one is any better or more supportive than the other because what is under the mattress will make a difference in the feel and performance (with the thinner one especially).
The difficulty of course even with a “fair” return policy is that they only have one memory foam mattress and two latex mattresses so if you do decide on an exchange then there would be no other “equal value” mattresses to choose from of the same type. while they are good value IMO … if you did decide to go in this direction I would make sure you chose on the firm side if anything so you would have “room” to add some additional softness if necessary because you can’t make a mattress that is too soft firmer without removing layers.
The members of the site that sell online are listed in post #21 here. There is a wide variety of different choices and designs, some excellent quality and value, and good guidance available there and some very good exchange and refund policies as well that can help make up for the extra risk of an online purchase if local value or choices aren’t so good.
There are other local options as well of course that would also be worth including in your research and could at least give you some good reference points about different materials and layering if you did decide to go in an online direction.
Phoenix