Re: I dont understand full stacks
I think full stacks are overkill. However, I think anything smaller than a 4x12 for my application is compromising.
For those claiming that the PA can do the work, I wish I was playing in the clubs that you are playing at when I was playing in bands over the last 9 or so years. I can probably count on one hand how many times I've played a venue that had a PA that was up to snuff, and surprisingly enough, it wasn't that uncommon to have a sound man who would not dedicate a channel to my rig.
And in those venues that actually had a good PA, no effort was put into getting a good mix in the monitors. The sound man only cared about what the audience heard, the headlining band and getting in-ear monitor mixes right. If you weren't touring with in-ear monitors, you were basically left to your own devices. And a 2x12 pointed at my ankles wouldn't have done me any good, in respect to being able to hear myself, unless I played with my ears at knee level.
For these reasons, and the fact that I've never heard a 2x12 that sounds as good as a 4x12, I think that a 4x12 is a pretty good choice for musicians on the road who don't have huge roadie crews and massive tour budgets. If you're just playing bars, a 2x12 will probably suffice. But for me, I couldn't imagine not having a 4x12. But, getting back to the topic at hand, I find full stacks completely impractical. I toured with two half stacks and that was torture enough.
And as Happy Dude mentioned, the balance thing is a real concern. I've played on a lot of shoddy stages. I wouldn't dare risk placing a $1.5k-$2k head six feet off the ground so it could get bumped into or rocked off it's perch only to fall to its death.