years ago I used to do my own projections. I put a lot of time and Excel horsepower into a system where each projection was automatically balanced - team passing yards = team receiving yards, etc. This type of thing really bothered me, because as an engineer I like nice, closed formed solutions to things.
I stopped worrying about this though, because I found it a waste of time thinking about reception distributions of WR'4, WR5, WR6, RB2, TE2, TE3, FB, etc. These aren't guys anyone will draft, so who really cares?