I've always heard heavier line gives better action to topwater plugs but I don't know. Just go fishing. Don't make the bass smarter than you. The most important thing to me is, is that my line is properly matched for my rod. I catch bass using 20 pound mono with a zara spook and unsing 8 pound mono with a rapala. make the rod, line, reel and plug match one another and you'll be ok.