Hi johnti006.
Welcome to our Mattress Forum. 
It looks like you’ve put a lot of thought and research into your configuration. Mattress-mattress matching is a very difficult thing to do (which more often than not proves to be a futile exercise). You might find it helpful to peruse post #9 here which describes several ways that one mattress can “match” or “approximate” another one. There are also several factors that can affect how soft or firm a mattress (or an individual layer) feels besides just the exact specs, density, and ILD of the foam used (see post #4 here for more information )
That aside, I do think your proposed set up looks appropriate for your heights/weights/sleeping positions. You did mention that you’re questions the 3" in the comfort layer. For you, as primarily a back sleeper, 3" may in fact be excessive. 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. And for your wife as a combo sleeper, it is usually wise to choose a comfort layer that is a little thinner than your “deepest” sleeping position would normally require (typically side sleeping) and then choose a support layer underneath that helps to sink in a little extra when you need it.
I am not sure if any of the above will prove useful to you as you move forward, but I certainly hope I’ve offered something here that can help.
NikkiTMU