in the old days, the grips were a shorter so there wasn't a need to worry about them intersecting unless the customer had an extreme amount of lateral due to an injury or crooked finger tips. Now the grips go, I believe, like a full inch deeper.
I was taught the recommendation of 7/8" difference in lateral, as we started to get layouts like the Double Thumb and MOTion Hole layouts which needed deeper than normal depth. 3/8 Lateral in the middle and 1/2" in the ring were the standard and my personal laterals and were to be adjusted for customer comfort. Anything inside of 3/4", I inform the customer that they are voiding the warranty of the ball.
Gluing the grips in isn't really a problem unless the have extreme F/R pitches like 3/8" or more, mine being 5/8" rev, that would cause the grip to stick up. Even then, a little deeper in the fingers and gluing from bridge out cures that issue. if any cutting is required, I normally do it at the top and wipe edges with Acetone while wearing gloves. Works like a charm