I think the style and efficiency of the offense should dictate Spiller's use. Use him early and often. Try to take a lead. If you can take that lead, come out with a heavier run game and use Fred more.
It's kinda dumb to get wraped up in the # of carries. What I'm concerned about is impact on the team. Spiller had similar impact to his offense, that AP had to his. With way fewer touches. He legitimately was at AP status last year.
I am in the camp that Spiller can't carry the ball 20+ times a game; but who cares? All Day is All Day, and that is part of what makes him great. Spiller can absolutely handle more touches, but I want to see him in the slot, screens, routes out of the back field, all the stuff AP doesn't do much.