A few things:
1) Distribution refers only to percentage of plays designed for a specific player to shoot. However, if he's your PG, assume he's doing a good bit of ball controlling anyway.
2) I would not be overly concerned with an individual player's statistics: I think you'll find that even more than RL, HD is far more of a team-oriented game -- for example, if you look at the top teams, more often than not you'll see extremely balanced scoring across the board, as opposed to RL teams that have 1-4 guys scoring significantly more than the rest.
3) Most importantly, assists are the least important stat in HD. You can artificially raise them by hving your PG never shoot, but at what cost? Find the conbination that results in the best team outcome: if Huffman's shooting 46.7%, don't lower his distro -- he's still passing the ball every time he doesn't shoot, and more passes probably won't result in anyone else shooting any better than that anyway.
Then again, I can never get the triangle to perform the way I want anyway, so maybe I'm the wrong guy to ask...