I have what some will say is a long span (5 5/8). I use zero pitch in the fingers, 1/2, 3/8, respectively side. I use 5/8 reverse in the thumb with 1/8 side pitch. (I've never used grips.) I'm aware of only one bowler whose span is similar in length, former touring pro Don Genalo. His pitches are different than mine, namely a zero pitch in the thumb and 1/2 side pitch; he's never been mistaken for a high rev bowler.
My rev rate is between 400 and 428. In my case, I need reverse pitch in my thumb. I've had ball drillers in the past who weren't used to span lengths like mine and drill my pieces as much as 3/8 short in span. I've also had ball drillers go with less than 1/2 reverse (like 3/8) in the thumb. In either case, not drilling my pieces correctly was uncomfortable, sometimes painful, and negatively affected my game because I couldn't get the ball cleanly off my hand.
Urethane Game said it best. A bowler who uses good mechanics and leverage can generate a good bit of rev rate based on their physical capabilities. It also helps when equipment is drilled to fit the bowler and it is comfortable for the bowler.