Cranking down the limbs will be less performance. You want to keep your limbs and draw weight as close as possible.

My best-friend has a EX-VFT. He has the 60# limbs maxed out at 63# He has a 28" draw length, with all his goodies on, and shooting a 27-1/2" Easton Carbon Epic (with 100 grain field tips), he is getting between 260-270 f.p.s.