First - It's about effing time!! 8)
Second - I'd personally be hesitant to place omnis that high. This may be part of the cause of the exaggerated percussion. Bear with me and I think you'll understand.
Imagine a triangle.
Point 1 is the microphone.
Point 2 is the front of the orchestra
Point 3 is the back of the orchestra
If you were to place the microphones (point 1) at the exact same place as the front of the orchestra, you've now got the largest delta that you can have as far as distance-to-point-2 and distance-to-point-3. In other words, the sound will be very deep as the sound from the violins will arrive immediately, but the sound from the trumpets will take perhaps as much as 25-30 ms to arrive (for a delta of roughly 25-30ms)
However, if you move the mics (point 1) up in a vertical plane to say 10 feet, the violin sounds will arrive at the mics at roughly 8.8ms but the trumpets will still take around 25 to 30 ms (let's assume 25 since I don't think the hall is that deep. This will account for roughly 30 feet of depth on the stage). Now your delta is only 17 ms. This makes the trumpets (and bones and percussion) sound much closer.
The higher you go, the smaller the delta (you'll never reach equality unless you move the mics over the orchestra.....you wouldn't do that!) which means the more compact the orchestra.
Listen in the hall. Are the percussion that loud in the hall? If so...there's not much you can do (shy of telling the conductor the percussion are too loud! Unless you know him/her and have a VERY good relationship with him/her, this is not a battle you want!)
I am very inclined to agree with you - if the hall sounds VERY good, omnis are (IMO) the best way to go. Spacing is critical, especially if they're to be the only pair. If they're not...you can afford a little sloppiness on the order of a few centimeters. If you're flying mics, this can be a MAJOR pain unless you have a ladder or a hydraulic lift. Even still, this can be a pain in the butt and this is why ORTF is almost always a "safer" bet. A well spaced ORTF has the luxury of several feet of front to back motion before it gets to sounding wrong. Otherwise, I'd call it varying degrees of right...
Honestly, I have not listened to your links since I'm on a laptop right now and this would not be a good place to listen.
My only advice (blind, err...deaf) would be to consider lowering the main pair a few feet and consider angling them downwards into the orchestra. Try to make it so as much of the orchestra is on-axis or within 15 degrees as possible.
Also, I find the distance and the spacing to be a tad different than normal. Normally, with omnis in a good hall, I would go back at least 4 to 5 feet, maybe as much as 10 (given the depth of the hall). I understand the size restriction on the hall driving your choice, but in this case, I would strongly urge going with an ORTF pair with omni flanks. The 40 cm spacing seems as though it's also driven by your close placement. Generally, this is relatively narrow for a solo AB pair for orchestra.
The nice thing about the ORTF with omni flanks is:
1 - ORTF is a good deal safer than AB and is more tolerant of non-perfect halls.
2 - Distance is a little less critical
3 - The omni flanks can be brought in as much or as little as you'd like to add that width and breadth that you mention (and do it quite effectively).
With a hall that size, I would assume that the natural reverb of a full orchestra is a little top heavy. The ORTF/Flank combo will do a little to tame this and will allow you to add a slightly more appropriate reverb in post.
Of course, you'll definitely want more than a foot distance from the back of the conductor with ORTF. 7 to 10 feet would be a good starting point.
I'll listen to the samples in a bit and provide additional feedback if required.