Hi reneegavin,
Having a split configuration won’t result in a “crater” because the ticking fits around the latex layers very tightly and the latex itself is rubbery and “squishes” together tightly so there is no noticeable gap. The wool quilting in the cover also serves to “even out” the surface. Having said that … if the ILD difference between the layers was significantly different … then there would be a more noticeable difference between one side of the mattress and the other in the middle “transition” area. For most circumstances this is not an issue and the benefits of “split” layers when it’s needed far outweigh the feeling of any difference between the sides.
One of the challenges of belly combination sleeping is that the needs of stomach sleepers are directly opposed to the needs of side sleepers. Stomach sleeping carries the risk of sleeping in a swayback position (the heavier pelvic area sinks in too far and hyperextends the back). Because of this … it normally requires thinner comfort layers in the mattress because the most important priority is to keep the back in the best possible alignment. Side sleeping on the other hand requires thicker comfort layers to conform to the more curvy body profile of side sleepers to fill in the gaps and relieve pressure on the more pointy parts of the side sleeping profile. Thin pillows … or no pillows at all … are also best for stomach sleeping to keep the head as low as possible and keep the neck in good alignment while side sleeping needs thicker pillows to hold the head up higher to get the best alignment. Combination sleepers need a pillow that can be both flat enough for stomach sleeping and “scrunched up” to give enough support for side sleeping.
As far as putting the bed together … with two people it is not that difficult a job. The trick is to “wave” the foam into position rather than pulling and tugging at it (latex is “sticky” and can also tear if you pull on it too much). Most people have no problem putting it all together and it can actually be quite fun. It can also be a bit of a “chore” re-arranging layers but that too is a side effect of the benefit of having layers to re-arrange and once you have the best layering then it doesn’t need to be done again.
Sometimes it makes sense to do some testing on latex mattresses that are available locally to get a better sense of the layering that may work best for you and use that as a guideline for ordering online. Without that though … Shawn is good at recommending what most other people with a similar weight and circumstances would normally end up preferring.
You’re right about the slatted KD foundation that Habitat sells. I seemed to “remember” that they didn’t sell one but they have had the KD slatted foundation (which is also widely available in many places) available for some time. Either way though, IMO a sheet of plywood on a metal frame is not the best idea. If you were meaning to buy slats and add them to a basic metal frame … then of course the height would be very low and you would want to make sure the slats were well secured so they didn’t fall through and “surprise” you. In general … you need a slatted system where the gaps between the slats are no more than 3" apart (at the most and preferably less) or a wire grid type of foundation.
I also realize I didn’t answer your comment about the different types of latex in your previous post and there is an article here which will explain the differences between Dunlop and Talalay … and blended and all natural. There is more information in post #2 here as well. SleepEz also uses different suppliers for it’s latex but unless you have a strong preference for one supplier over another then I wouldn’t make that an issue because all of their suppliers are good ones for both their Talalay and Dunlop latex.
Phoenix