There are two different kinds of tickets drops: 1) at the arena and 2) on TM.
As far as I know, each concert has had day of concert ticket drops except Vancouver2. (I've heard that the drop for Van2 occurred during the day for Van1, and all Van2 tix were snatched up at that time.) Those drops were made primarily at the arena, and included quite a few GA's. Glendale, however, had some amazing seated tix pop up on TM during the day before and the day of each concert.
Seattle had numerous ticket drops that were spanned out over two months on TM. In fact, I posted on here a couple of times saying that I was pulling up 8 tix (upper level $95 tix) at a time.
One thing I neglected to mention was that Seattle and Denver (and Glendale, just to pile on) were soft markets on this tour. As a result, there was a greater chance that (a) excellent tix would be "dropped," and (b) more tix (in terms of quantity) would be dropped. Both were possible because there probably were fewer VIP holdbacks.
By comparison, LA1 and LA2 had virtually no tix released on TM. Chicago 5/7 saw a trickle of single seats released today on TM. I expect the same to happen with NY1. (Philly and New Jersey are tough to gauge because a lot of the arenas are publicly, ehem, politican-owned arenas, which likely means friends and families of politicians will take the VIP tix.)
If history is any guide, I snagged excellent behind the stage tix (for each concert) literally days before the post 9/11 MSG concerts. In other words, do not expect better than behind the stage seats to be released at MSG, at least through TM.
I hope what I've written is coherent. I'll write up a thesis for the next tour!!