What would two 2" latex toppers stacked on top of each other feel like in comparison with a single 3" topper?
Specifically, stacking an 2" topper with ILD ~15 over 2" ILD ~19 in comparison with 3" ~ILD 19?
Would the 4" combo be warmer than the 3" single topper?
Would the 4" combo be better for side sleeping, or back sleeping?
Would the 3" topper wobble less?
If on top of pocket coils, would the 4" combo negate the pocket coil effects moreso than the 3" topper?
Hi 4dream.
Welcome to our Mattress Forum. 
Stacking a super soft 15 ILD 2" over a nearly-super-soft 19 ILD 2" will differ in the amount that you sink in in comparison to a since 3" 19 ILD topper. Unless you are ultra-light and ultra-petite, you’ll likely sink right through that top layer into your second soft layer, which will “cradle” you but potentially not offer you adequate alignment or support. You can learn more about that here.
I can’t say for sure, but it’s unlikely to be much warmer than 3" and, of course, your bedding also has to do a lot with what makes the bed warm vs cool. If you’d like more resources and information on that, let me know.
A lot of this is dependent on your own sleeping needs and preference. Most side sleepers will fall in the range of from 2" -4". A good starting point for a back sleeper is 2" of softer material on top of your mattress and then increasing or decreasing from there depending on other factors like weight, preferences, or other sleeping positions.
Are you referring to potential motion between 2 toppers that are not glued together? It shouldn’t be much of a problem either way. It also depends on your definition of “wobble.” I have a 3" memory foam topper that I hate that I feel like gives me motion sickness and I refuse to sleep on it haha.
Neither topper should be negating the effects of the pocket coils. If you dislike the feel of coils, I’d suggest an all foam configuration.
NikkiTMU