for drifting i'd spend the money to get a larger bag for high winds then a smaller bag when not so windy. I've used 1 big bag tied in the middle then I've used a small bag on the rear and the big bag up front. for trolling its best to get trolling bags and not drift socks. if you plan on doing both get trolling bags. i have a 36" and a 30" bag on my boat and haven't had any problems running them while trolling. and on calmer days I've just used 1 bag with no problems with boat control. but i have a smaller boat, its 21'.