^ I listened to this this last night. Thanks for posting, and please take this as a hopefully useful constructive critique rather than negative criticism-
This one has a few problems as I see it.
To my ear this is a situation in which omnis may not be the best choice, as well as an example of a significantly wider than optimal mic arrangement. Cool looking venue, but based on the archive page photo looking toward the stage (which I presume was taken from the recording position in the balcony) it is IMO too far back in a boxy room for omnis, making their contribution overly reverberant. If it were more appropriate for them I'd want to bring them closer together to about half that spread.
In addition, when spaced omnis are wide, a center pair arrangement that tends toward a more center-solid presentation is helpful to really anchor the middle of the playback image. Think of it as sort of serving to balance the scale as a counterweight to what the wide omnis are providing. DIN and the other common near-spaced stereo configurations that work well for two channels represent something of an optimized balance of width and center solidity when they are used on their own. When combined with the over-wide omnis, the result can tend to be a bit weak in the center. That's one reason I like a coincident pair in the center. It's sort of the opposite of a wide spaced omni pair, so that when properly balanced against each other, the inherent strengths of each pair serves to help with the inherent weakness of the other.
What might have worked better?
If not changing things too much and keeping the near-spaced center-pair, I'd retain the same spacing but narrow the angle from that of DIN (90 degrees) to PAS, switch the omnis to directionals and move them in to about 6 or 7 feet total. If it were me running my own stuff, I'd likely run the OMT4 arrangement I posted about above, with a PAS near-spaced supercardiod pair spaced a couple feet or so total, plus a Mid/Side pair in the center. If I wanted to run omnis too just to see if they'd be helpful (6 ch total) I'd bring those in to about 6-7 feet apart as before, and if the front of the balcony edge was a flat surface I might tape them directly onto it to boundary mount them facing forward, which will help increase clarity and is easy to do with small lightweight omnis like the AT853s.
Thanks for posting and kudos for the spirit of adventure in pursuit of good tapes!