Following up on my other thread about a solo boost in the FX loop, Stitch mentioned dropping the volume for rhythm then turning up for leads.
After fiddling about with tubes (ended up taking out the Tung-Sol in V1 and replacing it with a Mesa as the Tung-Sol just had way too much gain to let the drive channel 'clean up' with my volume knob) I started re-tweaking my TS7 to get things going again.
Common wisdom here is that 'boosting' a high-gain amp with a Tubescreamer for rhythm sounds tightens up the low end thanks to the Tubescreamer's mid hump and cut on highs and lows. I never really noticed it on this particular amp as the drive channel is very smooth, middy, and a bit loose, and boosting it doesn't really tame the 'looseness' very much.
However, the drive channel has a fantastic lead sound unboosted, but is a little flubby for rhythm, boosted or no. Turning down my guitar volume tightens things up a bit, but still leaves some of that bottom in there.
Thinking back to Stitch's recommendation, I set my TS7 for a clean boost, then dropped the level knob to actually result in a moderate volume drop with the pedal engaged.
Suddenly, I can step on the TS7 to get the tightening effect of less signal and the EQing effect of the Tubescreamer circuit all in one, resulting in a tighter, crunchier rhythm sound that works very well for what I do. For leads, I turn off the TS7 and I not only get a slight volume boost, but the amp smooths out and saturates a bit more. This allows me to run my gain a tad higher for a smoother lead sound yet not have the looseness issues on my rhythm sound.
It's amazing what happens when you turn knobs and listen rather than going by common wisdom. I can't wait for rehearsal tonight so I can try this out in a band context and make sure it all still works!