Hi DachsieSlave,
First a big thank you to Phoenix, for this website. I've learned a lot this weekend just reading "not studying" as directed
Welcome ... and I'm glad you found us and that the information on the site has helped you.
Any way I know my weight brings along a need for extra attention to construction. So after careful research I believe I have narrowed it down to the #BME and Aloe Alexis. They both seem to have the quality for my weight and I know the feel difference only I can decide. But would the extra Latex of the Alexis give more durability and a better chance of getting me the right feel and support to make double the price a better "value". Also would the changeable layers come in handy if I lost the weight, would I want a different feel?
While both of them use high quality materials and there are no lower quality materials or weak links in either of them ... in your higher weight range the extra 2" of latex in the Aloe Alexis would give it an advantage in terms of durability yes.
The Alexis also has more options to "fine tune" and customize the pressure relief and support of the mattress both before a purchase and after a purchase as well (by either rearranging the latex layers or exchanging a layer) compared to the #BestMattressEver which is a "finished mattress" that has 3 firmness options to choose from but can't be customized after a purchase (outside of adding a topper).
Of course the #BestMattressEver is also a lower cost option and has a longer 120 day trial period with no cost involved to return the mattress if your choice doesn't turn out as well as you hoped for while the Aloe Alexis has a 45 day trial period with a $99 cost involved to return the mattress.
The replaceable layers in the Alexis would also give you the chance to replace just a single layer down the road if the top layer softens or breaks down before the deeper layers (which is most likely) or if your needs and preferences change down the road (possibly as a result of your weight loss) instead of having to replace the entire mattress.
And last I really want a new mattress now, but would it be better to wait while my back is straightened out so it wouldn't effect my perceptions?
This is more of a medical question that would be more appropriate for your doctor than for me but I would think that having a good quality mattress that keeps your spine and joints in good alignment would be important regardless of the condition of your back.
I would also make sure that you talk with both of them because when you can't test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help "talk you through" the specifics of their mattresses and the properties and "feel" of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best "match" for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the "averages" of other customers that are similar to you. They will also know more about "matching" their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
Phoenix