Thanks for the comments above.
I got in a brief listen last night, hoping to return to it again with more time tonight. I noticed low-frequency overload distortion happening somewhere. Could be the omnis, maybe the PA, maybe something else.
Your comments on the usefulness of the shotgun are right in line with my thinking regarding the intent of including it. The goal is producing a recording you are happy with, so no worries about not spending hours playing around with various channel combinations afterwards. I tend to do do a lot of that kind of listening, partly as an empirical check on what I think I know about how these arrangements perform, and partly as reconfirmation of the hierarchical order of importance of each addition in the progressively increasing channel count.
Some thoughts that come to mind about interesting possible combinations with this arrangement - not suggesting you try listening this way, just fun for me to think about and float ideas out to whomever may be following the thread:
● The most obvious comparison is X/Y center + omnis, with and without the shotgun added.
● A comparison I always find interesting is between X/Y stereo center (+ omnis) verses L/C/R stereo center (+ omnis), in this case the L/C/R triplet consisting of the AT 3031 near-spaced pair + center shotgun.
Here's some interesting ones this particular combination makes possible-
● Flip polarity on the right X/Y channel and sum left and right X/Y channels to derive their difference. Use that as Side channel along with the shotgun as Mid. This is using the X/Y pair as substitute for a fig-8 mic, producing a Mid/Side center pair with the shotgun.
● Comparison of that Mid/Side center + omnis with the straight X/Y center + omnis.
● A comparison of L/C/R + omnis, with the same plus the introduction of some Side channel to taste (more or less an alternate "all channels up" configuration). This tends to be the way in which I find the most appropriate Side channel level when I have both a Mid/Side coincident center and near-spaced pair. Essentially realizing the same could be applied to X/Y + near-spaced pair as well.. an alternate way of tweaking Mid/Side ratio to best effect.