Replying to Sir Francis Bacon Mounting Question

hey NS,
I picked up a pair of 179cm bacons and a pair of FKS's. I'm 5'11" and 200lbs with a pair of tecnica demon 130 boots and was wondering if I should mount at the recommended (-20mm I think) or go farther back around the 30-35 mm mark. I ski pretty aggressively some backwards stuff and minimal park. I'm more worried about all mtn performance and not whirlybirds so if anyone has any experience or input it will be greatly appreciated!