[FONT=Arial, Helvetica, sans-serif]Your choices are soft (22-24 ILD), medium (30-32 ILD), firm (38-40 ILD), extra firm (44 ILD) copied from Sleep eze site for my and your reference.[/FONT]
[FONT=Arial, Helvetica, sans-serif]Can't remember if you have natural or blended. If 2.8" or 3", and if natural a bit firmer. Refresh my memory please. I have 8.5" over a mattress (LOL) so I would bottom out if the layers weren't firm underneath and a mattress. I would definitely call Shawn tomorrow, oops Tuesday (holiday remember) and tell him your weight once again, and your situation. Perhaps you can add another layer and mail back the cover to get a 13,000. Or if they won't do that, option 1 add another layer over the mattress top like Mark has done, and some of us others (me)[/FONT].
You are close to my weight so you may need more layers, or firmer layers. but I still would want a comfort layer of 24ILD (S) . Can they do what Flobeds does and request a higher ILD of the top layer? Not sure if 22 to 24 is that big of a difference. But your medium and firm may be the lower ILD's, if label doesn't say, then SOL. I almost think you should try changing the medium to firm, and the firm (MAYBE) to extrafirm. Just throwing ideas out there.
Did you read the persons posting under yours, they have a 13,000 and the husband has lower back back, and the wife feels it is too hard. So Princess and the pea. I think they said it is on a box spring. Personally I think you may consider either a Euroslat or ??? It is so hard to figure out for someone else, let alone myself. I know people think I am nuts having a spring mattress and then 8 1/2" latex, but you know what? It works for me. I like the springiness and I didn't like laying anywhere near the hard springs.
Do you still have your box springs to try putting the latex on?
I was going to say put the S over the F, and then the M for tonight to see how that is.
P.S. Put your frame on the floor and see if that firms up the latex and stops your squeaks (LOL).