You never want the difference in ring size to get too large - I think it's pretty universal that you never should go larger than 14. 50-34 compact cranks have the greatest differential at 16 and they've had their challenges with quick shifting and dropped chains though this is improving over the years. You can always add a Deda Dogtooth on the seat tube near the bottom bracket. A lot of the pros run these because they don't ever want to chance a dropped chain, no never.

The larger the gap, the longer to shift up and the greater chance of dropping when shifting down. This doesn't matter whether it is a double or triple crank.