It's all a matter of comfort. Along those lines, you have to find someone who is open and willing to drill according to what works for you.
I've had people who weren't used to drilling long spans drill my pieces as much as 3/16 short in span or damn near refuse to drill as much reverse as I've requested, saying I wouldn't be able to keep the ball on my hand.
I have span measurements of 5 9/16, 5 5/8 span; zero pitch in the fingers with 1/2 and 3/8 side, respectively. I also have 5/8 reverse in the thumb, with 1/8 side. (I've gone as much as 3/4 reverse in the thumb.)