Hi Martina:
Thank you for taking the time to reply.
The softening of the topper seems normal, especially as you are using only 3" and it is doing all of the work on top of a hard platform, not allowing any layers beneath it to “share the load” and dissipate your mass. The center part feeling firmer would certainly makes sense, as that foam hasn’t been used nearly as much. I don’t know that flipping will make too much of a difference with only 3" and the use that this has already had.
Your list is a good place to start. The change from 28 ILD to 44 ILD will be noticeable, but the 44 ILD will be more appropriate and durable if using only 3", and it may more closely approximate some of the firmer surfaces you mentioned in some of your older posts. Of course, only your own personal testing will tell you for sure, so if you end up purchasing something without trying it out be sure to check into any potential return/exchange policy in case things don’t turn out as you had hoped.
All I have in Yuma is here, but these are not latex component stores:
Denver Mattress® - The Easiest Way to Get the Right Mattress They are a factory direct regional manufacturer that has a wide range of mattresses but one of them is the iChoice which is a mostly Talalay latex mattress which has a separate Talalay latex topper.
mattresswarehouseofyuma.com/id4.html Yuma, AZ. They carry Stress-O-Pedic and Sherwood and neither one has an all latex mattress but they may have a latex hybrid on their floor. If you decide to go here I would call them first to see what they have on their floor and to make sure that there that any “latex” mattresses they carry have more than just a thin layer of latex mixed in with other materials.
Other than that the San Diego list would be your closest source of latex that I can see and there is a much wider range of options there.
Phoenix