It means something when you try and compare a cam that you can nearly reach peak lift #'s with 1.95 rollers...and he already has rockers last I checked. So if he is going to be running the rockers with the VS, I hope he knows he can't exceed .550~ peak lift on the stock valve guides.
Furthermore; You can run the same valve springs, the same retainers, and see more gains from an S1X, XP, or even a custom grind...more flow = more room for extra timing/leaner AFR/smaller pulley...which increases the gains even more over just the difference in the grind.
Not saying you can't do it on a VS but there are other options.