It's not about who starts but about who plays with what rotation.
I couldn't care less if Sully or Bass starts. What I do care about is Sully getting touches on the block, since we need that presence and he is that kind of player. I think he fits best with KG on the floor in this regard, since KG can spread the floor and take away whatever shot-blocking big that may harass Sully in the paint.
Conversely, with Bass on the floor, KG has to be in the paint more (not necessarily a bad thing, though he doesn't like it) - we learned many times last year that we can't rely on jumpshots to propel the offense. KG can be an All-Star on the low block but we need to preserve him, especially against centers.
So my preference is Sully + KG more than Bass + KG. Does this mean that Sully starts? I don't know, but I guess so.