Should I use small height and rear speakers?

[soundwave628]

Ok thanks a lot, I guess I'll mount the "better" onkyos as front height channels and the lesser ones as rear surrounds. I haven't had the room to set up 7.1 yet and I really would love to have it for movies and more directional awareness in video games. Maybe after I get a nicer subwoofer I'll get around to a better receiver and maybe even amps but money is tight and I'm trying to get as much as I can out of this onkyo HTiB.
Ugh something just dawned on me. When running 9.1 will the lower wattage going to my speakers be noticeable to me? It should come out to just over 100 watts per channel and right now I'm actually running my monitor 70s bi-amped, though I've read that doesn't even make a noticeable difference to most people. Also when I upgrade to a powered subwoofer will that unused power from the receiver automatically go to my speakers?