It's more theoretical than anything. Having a slower spin puts less pressure on the bullet. Benchrest shooters have the slowest spin possible for the bullet they choose to gain that extra hair width accuracy and a few fps of speed. It shouldn't matter with a hunting rifle.
A point of information, the 6.8 spc was originally speced with a 1:10 twist. This twist is the usual twist for a 270 Winchester shooting 130 grain bullet. This was changed to a 1:12 twist since the 6.8sps uses shorter/lighter bullets than the 270 Winchester traditionally does. By changing the twist, they were able to get more velocity with less pressure. (This was after elongating the throat to reduce pressure.)
So, having a slower twist can make a difference in some cases but in most it's purely theoretical. In the 7-08 the 1:9 twist is pretty standard and works for all ranges of bullets.