I think this is a good point, and it's a big reason why I hope Scola can starting playing more consistently with bigger minutes and maybe replace Chuck as our starting PF. If Rafer can somehow maintain his current level of play even when McGrady returns, then maybe we can get away with starting two extremely low-usage offensive players like Shane and Chuck. I can't see that happening, though.
Chuck Hayes should be the starter for now until Scola develops himself on the defense end. On the offense end Scola has proven his worth but his time will come. Hayes is very good at his job which is rebounding and defending and indeed he misses a shooting touch. I'm glad i haven't seen him shoot before but i heard about his FT shooting and it doesn't sound too well. If he can inprove his scoring ability he will be a good starter but he will never be a true PF. So Chuck Hayes and Scola's minutes need to be the same imo and maybe try to start Scola a few more times to see what kind of impact he can make.