Perspective of the 35+ player
OK, I am gonna express an opinion that might get shot down here, also, I might not have wanted to hear this at 17, but........
What sort of PA are your band using?
I am asking, because if you have a PA that uses bass bins and is big enough to handle the bass within the PA, then I do not see the point on buying the biggest, loudest piece of kit on the market, so that you can cope in big venue's - I say let the PA do that. Go for reliability from quality kit with the emphasis on monitoring.
(Again Opinion Only) it is a case of educating all the band, perhaps with the exception of the drummer, that loud out front, does not need to equate to loud on stage. Our keyboard player now has tinitus from having his monitor stand-mounted at ear level for years.
I have a 300watt head into a 2x10 cab, which I never need to have at more than 50-60% volume and the band can hear it and I can also hear everyone else. Both my brother and I (our guitarist) are currently setting up new Line6 POD xt Live units which will connect straight into the PA and therefore the backline will purely be monitoring at sensible levels.
I stood in with a band a couple of weeks ago that usually have no backline at all, only quality in ear monitors. Therefore there is no sound on stage at all, as the drummer uses a Roland electronic kit.
Anyway, I have been rattling on like an old man, but youth is all about rock n roll and you can worry about your hearing and stage volume when you are in your thirties.
Enjoy playing and good luck with the search for gear.
can come to some amicable terms that help you both out.
lol...and wen i have my two guitarist playing through vintage all valve marshall heads silly amounts of cabs i would feel a bit stupid....just my teenage ego i spose.... 
