I don't think you will see much difference from Bush's FF points whether he starts or not.
If ALL the RB's were healthy then the way Payton gameplans Bush could "start" even then, to the extent that means a HB is in for the first play. But Bush still isn't doing much as a runner, Payton won't be waiting for him anymore in that regard, even with that nice little (and somewhat surprising 19 yard TD jaunt last week).
PT is an uncertainty because he has or had a brace. Who knows what that does to him. Payton has gone for the power RB game all the way, and I think Hamilton can fill the Bell roll. In fact Hamilton had a terrific preseason game where he did just that. If PT plays and doesn't produce straight off then don't be surprised to see Hamilton come in and do a good Bell imitation, and he can do it.
I would start Bush if you ordinarily start Bush, not if you don't. I wouldn't start PT until we see how he is (I wouldn't be surprised if he has a good game, but who knows really); and I would not be surprised if Hamilton has a great game, but it's purely a question of how PT is health-wise and how he runs.
Hamilton has been a training camp name in NO with upside for 2 years now.