@mistermikev In the beginning of starting Dr Bonkers Soundlab, I did a lot of testing of concepts for IR capture. I can't go into too many details since the field is so competitive now.
The audible differences of recording two 4x12 or 4x10 cabs on top of one another were negligible using my recording environment and techniques.
I specifically don't use room mics because, unless you are using the same room on everything else in the mix (live or recorded), the results sound disjointed to my ears, to put it kindly.
Multiple PZM captures and my figure 8 captures when mixed in with other mic IR captures can give you the depth most desire from room and back of cab mic ir files when mixed in at miserly levels while still allowing your instrument to sit well in a mix and cause no phase issues.
You can mix HypeReal mixes or or your own custom mixes together to make a virtual stack. I have a whole article and video on it here:
https://www.drbonkerssoundlab.com/s...r-using-impulse-response-ir-files-and-mix-it/
Please forgive my guitar playing in advance.