You're welcome! I mostly just like talking about LoL and strategy, haha.
If you're significantly better at a particular role or two, say that. If you're competent at most roles, say that. That way, your team as a unit can work everything out.
Every time I enter champ select, everybody sees the following:
RiotTiza: sup team =)
RiotTiza: I main ranged AD, but I can top/mid/support if needed
Then, depending on how much people talk, I'll either reiterate who would like to play what, or point out what roles are left and who hasn't called something yet, so something like:
RiotTiza: still need top/mid - can Summoner4/Summoner5 do that?
When in doubt, first pick gets priority, and I try to do what I can to make everybody happy. I'd rather give up my main role and avoid arguments in champ select than be stubborn.