Still not groovin' on the "Top" "Bottom" thing. I don't think that's a point of characterization. Now, someone's ATTITUDE or FEELINGS about the sexual acts and positions they enjoy certainly is, but not what they like in and of itself.
Brian clearly has an attitude about it, and so does Emmett although it's mostly humor, and Michael makes a comment once that he's "not a total bottom," but no one else seems to give it a moment's thought. So I don't think this belongs in the analysis. To say Brian is somewhat hung up on being vulnerable, as is Drew, is enough. We don't need to know what they do in bed to understand that about them.
And I still think Ben and Blake are far, far from opposites. They're IMO extremely similar characters, far more alike than Ben and Drew.
Also, Michael doesn't move from Brian to Ben. He moves from Brian to DAVID to Ben.
I know you're not locking people in here, but I have to admit I don't find this useful in understanding the characters. It feels like you have to kind of backfill them into the catagories rather than that you're truly describing them...
I'm not rejecting the whole concept, and there are definitely some interesting patterns here that I think are helpful in understanding both the characters and the inter-related storylines. I'm just saying, some of the terms and categories aren't right IMO.