From what I've read and my own experience.. chips are for quick aging. I've only done jars myself but if you have gallons at a time your aging I've heard many people say about a handful of chips. Now after you start to get some decent color.. probably a week or so I'd smell and taste it. After that every few days I'd give it a check as you can't take the woody taste back out. Maybe someone who has done this with bigger quantities can help you better.. I'd just stick to the nose and taste test myself :) Keep an eye on it.