Hi Al, that OMT6 arrangement pictured above looks good!
That's a funky room. Tall and wide but not very deep. I'd ordinarily say fly high to make the pickup of disinterested chatter less localized and more diffuse, but be careful to stay within the vertical coverage pattern of the PA speakers, which in those photos appear rather low. Essentially, the mics should be positioned so as to have a clear and direct line into the throat of the high frequency horns of the PA speakers, which means not positioned so high that they end up outside of the good coverage sector defined by an imaginary extension of the high frequency horn walls out into the room.
Not sure of the sphere's on the omnis, which is something you may want to play around with moving forward. With that 3' omni spread in your OMT6 array, the omnis provide good bottom end extension and diffuse ambiance. I'd probably point the spheres directly out to either side to help with both (+/-90 deg), or at least +/-45 deg rather than directly forward.. more on that below.
I actually removed the spheres from my omnis at a fest in early October and have been recording without them since then, and think I'll leave it that way. One thing influencing that decision is that the tiny DPA omnis are near invisible without the sphere attachments, which sometimes allows me to extend the omnis further out than I might otherwise comfortably get away with, which is good since my preferred OMT omni spacing is 5'-6'. On that point- at a two night new years run last weekend I extended them fully out to 6 feet with no one noticing except one other local taper who looked up from directly underneath said "I think your rig is jammed up against some kind of wire running across the room", which I pointed out was actually not a suspended wire but the thin black TV antennas with the omnis mounted at the ends.
I've talked a lot about the sphere attachments in the OMT threads and don't want to rehash all that too much, but will sum up my current thoughts on them here..
1) I feel the spheres are most useful in more minimal microphone setups. They are often a great asset when using a single pair of spaced omnis on their own because they provide a bit more forward focus.
2) At the other end of the spectrum, I'm not convinced I need or want them at all in my current OMT8 array, in which I have directional mics facing forward and rearward, essentially covering all horizontal directions, and I'm usually able to get the omnis out to 5' or more. I feel that as additional directional channels are added to the array using the spheres becomes less important, yet they still remain useful if pointed directly out to either side when the omni spacing isn't as wide as I'd like. Pointing the omnis out to either side helps even without the spheres because it pushes the omni caps out somewhat wider than the mic-bar otherwise allows.
3) Other than pointed out to the sides, I go back and forth on how best to orient the spheres in conjunction with directional mics facing forward - especially with an OMT6 array where there are 3 or 4 forward facing directional mics. Without any rear-facing mics I think I may prefer them angled backwards so as to capture a more diffuse ambiance from all directions. That slight high frequency rearward bias partly fills the roll of dedicated rear-facing directional channels.
