Hi kelly500,
Sorry for missing them …
No … they could be very different. It would depend on the layer thickness of each layer, the ILD’s of each layer, the type of latex or polyfoam in each layer, the order of the layering, and the type of cover that was used in each. Some versions may be very imilar and some versions may be very different (and this would also be dependent on the more subjective perceptions of each person because different people are more sensitive to some differences between mattresses than others).
It’s usually best to “rate” each mattress against a common set of “standards” (such as the ones in post #2 here) … especially in terms of the two primary functions of a mattress which are pressure relief and support … than to try and “match” two mattresses that are very different from each other.
I think that it would be more accurate to say that with a one sided mattress … flipping is not possible rather than not “necessary”. Even with more durable materials like latex … a two sided mattress would be more durable than an “equivalent” one sided mattress but the tradeoff would be that there is less flexibility in the layering possibilities of a one sided design. Almost everything in mattress construction involves tradeoffs and the differences between a one sided and two sided design is no different. All other things being equal though … a two sided design would be a “durability bonus” and may also be a little more costly because it is finished on both sides instead of one only.
There is a foundation thread here which includes information about many different foundation options but if I was choosing an all latex mattress to go on a wire grid frame … I would personally choose a frame that had more wires and less gaps in between them (such as the ones that are mentioned in the foundation post that have 11 wires) if the mattress was directly on top of it.
You won’t need a foundation or bunky board on top of this type of frame and whether it was a good idea would depend on how securely the foundation or bunky board was on top of the frame. I personally wouldn’t go in this direction and would tend towards risers under the legs instead. If you did decide that it would be OK (for instability or shifting) … then as long as the foundation or bunky board was firm and non flexing and had no more than 3" gaps between the slats (preferably less) … then the wider gaps of the wire grid frame wouldn’t matter as much with a foundation or bunky board on top but again I wouldn’t tend to go in that direction.
Hope this helps and hopefully I answered all your questions this time
Phoenix