Keep the overhead condensers as close to ceiling as possible to avoid the reflections. Put a heavy blanket or whatever up there if possible.
Just curious...why distance the overheads farther from the kit? Won't that just provide for more room sound relative to direct sound? Seems like that would make for an even roomier sound than getting them as close as possible while still covering the kit.
I've only mic'd a kit a few times so I'll defer to your experience. In theory, it seems backwards to me. I'm supposed to mic a kit for some dudes in the near future, so I'm trying to soak up all of the tips possible!
The first reflection is the worst reflection because it's the loudest thing at the mic after the direct sound. For the overheads that would be the reflection off the ceiling. Your best bet may be to tape them right to the ceiling. No, it's not how it's usually done, but with your acoustic space it may be the least bad sounding option.
Let's say that I'm using a spaced pair of cardioid SDCs , facing generally downwards towards the kit. Since they reject most of what's behind them, wouldn't that take a lot of the ceiling first reflection out of it?