Keep in mind that when you're dealing with electrostatic-level resolution, source matters a lot. It doesn't matter that much for a HD595 or M50, but it can be everything with the 007 or 009. So when you're building your ultimate system, budget quite a bit of it for that. Otherwise, you'll end up doing what I did, which is basically buying one source after another until you learn not to skimp on it. Same thing applies to amps, though with easier-to-drive 'stats like the 207 amps matter less. But the 007 on a Blue Hawaii is a totally different animal from a 007 with a 313. Electrostatics are a HUGE money pit, and many friends I know stay away from them specifically for that reason.
Also, I should mention that stats can sound very different from one another. Even different versions of the same headphone can sound quite different from one another, like the old 007 Mk1 I have and the new 007A I just got. Some I like (this new 007A sounds killer) and some I flat-out hated (SR-404 springs to mind). Some I wish I never even heard (HE90 with the HEV90 was amazing, but dear Lord that price...)
Basically, what I'm driving at is - go to a meet, listen to the 009, and try a few stats for yourself to see what's what, which I guess is pointless advice since that's exactly what you're doing already
Lastly, while jumping straight into the deep end is cheaper in the long run, taking your time to learn what's what is a lot more sensible. I had a ton of fun experimenting, and while not all the experiments worked (and some were basically money thrown away) in the end I got a far more accurate idea of what I like and what I don't, and what I need to get to get there.