Naturelle Latex Mattress vs MFC Preso Latex Mattress

I’m currently in the market for my first latex mattress as I’m tired of sagging/sinking memory foam mattresses. I currently have a Saatva mattress which I’ve owned for 3 years and it’s started to sag to the point where I’m waking up with daily lower back pain. I’m primarily a back sleeper, weigh 195lbs and I’m 6ft1 tall. I live in Canada so looking at some Canadian options. I’ve narrowed my search to the following two:

  1. Naturelle Latex Mattress - $2,499 -
  • Comes with 3 layers of latex
  • Base Layer 6" GOLS Dunlop Organic Latex
  • Mid Comfort Layer GOLS Dunlop Organic Latex
  • Top Comfort Layer 2" GOLS Dunlop Organic Latex
  • Sales person recommended firm base layer for support and a medium-firm top
  • 90 Day Sleep Guarantee, No Haul Away Service but Shipping Included, Taxes Extra
  1. MFC Presto - $2,895 (No Tax) - Customizable Organic Latex Mattress | Natural Bed | MFC
  • Base Layer 4" Organic Dunlop Latex - Firm 40ILD
  • 2" Transition Layer Organic Dunlop Latex - Medium 30ILD
  • 2" Comfort Layer Organic Dunlop Latex - Soft 20ILD
  • Shipping & Taxes Included, $50 fee to exchange a layer for another layer within the 120 day sleep comfort guarantee period
  • Also comes with Lifetime membership which gives you 25% discount on all future orders of latex layers

This one is also customizable, I think I would want to adjust the firmness of the Transition & Comfort layers but was hoping to get feedback here of what I should be changing them to. Any feedback/suggestions would be greatly appreciated!

So I’ve received emails from both companies and I’m leaning towards MFC Presto. After a bit of back and forth he’s recommending I use the following setup:

3 x 2" firm core
1 x 2" medium center layer
1 x 2" soft top

Given the issues with my lower back aches, would this be firm enough? I don’t want to sleep on a hard rock but I also want to ensure it providers ample support.

I believe their firm core is ILD40, medium is ILD30 and soft is ILD20. All of them are Dunlop latex.

Would there be any issues with sagging or sinking with that soft top layer?