Hi FAUguy,
You would need some very sophisticated measuring and testing equipment to be able to calculate that. It would depend on the shape and weight distribution of your body and once you had measured that accurately then it would take some very high level math to figure out an algorithm that took into account the response curve of the different layers of latex and the changing surface area of your body as you sink in deeper.
Just for reference the ILD of latex is measured on a 6" core with a 50 sq in compressor head and the ILD is the amount of force it takes to compress the 6" core by 25% (1.5"). There is a video here for Latex International which shows their ILD testing (at 3:00) and one for Radium here (click step 9) which shows their ILD testing.
50 square inches is a diameter of just under 16" so the compressor head would be “about” the size of a bum. If you had a 24 ILD 6" core then it would only take 24 lbs to compress the latex 1.5", if the core was 32 ILD it would take 32 lbs, and if the core was 40 ILD it would take 40 lbs. I would guess that there is probably more than 40 lbs of pressure under your bum. I just weighed myself lying on the floor with a flat scale under my bum and it was putting 79 lbs of force on the scale (I weigh about 200 lbs) so if you weight 160 and your weight was distributed roughly the same as me you would be putting about 63 lbs of force on the same scale so your bum would sink into a 6" core of 40 ILD latex more than 2" if you do the “rough math”. Using the same math your bum would sink into a 6" core of 24 ILD latex more than 3" and probably closer to 3.5". Of course this is very “rough math” because I don’t know your exact measurements or your weight distribution and that would take much more sophisticated equipment.
There is also a more complicated (and probably not very accurate) example of some “rough math” with multiple layers in post #26 here and you can see a similar “rough math” example that applies to pressure relief (rather than how much you sink in) in post #2 here.
Having said that … regardless of how much you are sinking in or how much pressure you would have if it was measured … all that really matters is that you sleep well and as LJGMDAD said I would give it a few weeks at the very least (and hopefully you’ve checked the other suggestions I made previously as well).
Phoenix