Hi DariusFoxx,
Mark in Texas’s latest posts and updates hereYou can see (formerly Abraxas). He chose different layers and firmness levels than the Beautiful but seems to be happy with his design and I think is currently working on his cover. Hopefully he will see your post (he posted in another topic today) and will share his thoughts as well.
You can see my thoughts about a DIY mattress in post #15 here. It can certainly be a rewarding project if you have a “spirit of adventure”, your expectations are realistic, and you are comfortable with the learning curve, time, trial and error, and any additional costs that may be involved if you end up needing to change any of your layers.
Yes. There are some sources for mattress covers in the component post here.
If you use a suitable tight fitting cover (which would probably need to be quilted if you split the top layer) then generally no, there would be no issues with a split construction (see post #2 here).
ILD is not exact in any foam material but 100% natural latex has a wider range of variance in each firmness rating than the blended Talalay. There is more about ILD’s in post #2 here and more about the different types and blends of latex in post #6 here.
I would be aware that the PLB Beautiful uses blended Talalay (not 100% natural) in all the layers except the top layer which uses Talalay GL fast response.
Phoenix