Just get out there, jam with people; you'll know pretty quickly whether or not its going to "click". If you do meet someone and it doesn't feel right, just enjoy the opportunity, and then at the end be honest but gentle. Don't burn bridges, and don't lay any kind of trip on them. Just say it doesn't feel like a good fit, or the direction is not quite where you want to go, something like that.
If it goes well, (and this is the advice I think you need the most), be cool about it. Enthusiasm is great, but don't get ahead of yourself and start talking about record contracts or stadium gigs or "how are we going to manage our touring schedule when we hit the road?...". Just say "well, that was great for me, how about you guys? Would you like to do this again?" and then take it from there.
You like to think things through, and there's nothing wrong with (planning is good thing!) but don't get caught up in the "what ifs" of the "big picture" too early. Probably the #1 reason for indie bands breaking up that I've been privy to is people just getting way too wrapped up over power-struggles and non-existent issues "who gets what when we're famous?"... that kind of stuff. Thinking too far ahead can really be destructive.
For now, get together, play, have fun! When you start sounding good as a band, get out, do some gigs, and see where it goes from there. You've mentioned "unsigned" a few times. Just be aware that the glory days of getting offered a recording contract and being "picked up" by a label are pretty much over. Watch the documentary "Artifact" about 30 Seconds to Mars battle with their record label. Brace yourself, its pretty depressing stuff if you're hoping to live the dream of being a rockstar. On a more positive note, look into the career path of the band "Of Monsters and Men"... very different genre, but essentially all started with a indie folk artist in Iceland whose career took off very quickly. The music business is a very different landscape than it was back in the days of Guns and Roses... and its changing all the time. All the major labels are struggling these days, and as a result, are demanding much more of artist's revenue streams with things like "360" contracts. Musicians have to find adaptive ways to claim their income, as the model of "press an album and sell millions of copies" is fading quickly. But the good news is that it also means major labels no longer have a strangle hold on who can get exposure and who doesn't. As in the case of "Of Monsters and Men" their music essentially spread virally, and they were able to capitalize on their on-line presence.
Good luck, and have fun!
