Hi Karen S.
You are certainly looking in a great direction and as you know I think very highly of Flexus and they compete well with the best in the industry in terms of their quality, value, service, and transparency.
[quote]I am medium build and height and have had back surgery, but I need to “sink in” and love softness especially with my shoulders.
Is this correct for me?
bottom layer-firm
middle layer-med
top layer-soft[/quote]
When you can’t test a mattress in person then the most effective approach is a more detailed conversation with the manufacturer who will know more about matching the options they have with different body types and sleeping styles than anyone else and can help “talk you through” the choices that would have the highest chance of success (see post #2 here) but the layering you listed though would certainly be the most common choice for someone in your weight range based on “averages”.
Phoenix