Tube amp sweet spot vs. volume?

When you get in a band situation playing with other instruments you need to come down on the gain or you are going to sound like white noise, nobody is going to hear you no matter how loud you crank your amp. Come down a bit on the gain and your tone will cut through. :D

Excellent point. However, if you do want to use a ton of distortion, crank the mids and you'll really hear it. A lot of metal players cut their mids completely, to get the chunky riffing sound. If you cut out mids, a lot of times in a group your highs will blend with the snare drum and your lows will blend with the bass, making your tone hard to hear. Crank those mids at least halfway up and this problem mostly disappears.