Last batch I brewed (I'm brewing all grain) I used the same tool I used on my mead to aerate... Was in full active fermentation in under 12 hours (somewhere in the 6-12 range, was sleeping so hard to say more precisely)... Shaking a carboy puts more strain on my bad back than I care to... Hence creating a tool to do the job that fits into my cordless drill's chuck.
I would boil the largest amount you can, for partial boils. If you can do full boil sizes, go for it. If not, then the largest volume you can actually get to a boil, and maintain without killing yourself.
As far as being addicted to brewing, welcome... We have meetings, but they're not planned very well, or too far ahead. We don't stand up and say "my name is ... and I'm a brewer"... More like, bring bottles of stuff we've brewed (and want to share), have some good food together, some laughs, a generally good time, and then stumble home... Of course, if we can get together and actually BREW something, then it's all good. :rockin:
Don't be concerned if you have batches that don't show active fermentation for more than a day. There are times when the yeast need a little quiet time before they're ready to really party...
:fro: Give them the time they need to do all their jobs (2-4 weeks typically) and you'll be getting solid brews every time. Just be selective of who you share it with... Otherwise, you'll always be brewing in order to maintain your own supply (after others have raided you)...