Mitch2, I share same strategy:
IMO, it has nothing to do with tubes vs. SS, but rather does the preamp adequately drive the power amps, is it quiet and clean sounding, does it have body and drive, and is it musical.
In my approach lowest gain or unity buffered gain of preamp is the best surrounded by sources able to provide sufficient output level and sufficient sensitivity of poweramp. In other words fixed output components have large gain and variable output components have low or unity gain.