this is a good question. I like to do it 2 ways. 1 way is to place one or 2 next to or near something above the water so you don't have to use a gps to get back to it...You can hit it and run...The 2nd way I like is open water. We toss out 3 buoys (this way you never lose your set-up location) and get the tops in a pattern or line or whatever you want. If they're less than 7 feet tall I like to place 4-6 in a location. If they're those tall bad boys that my buddy builds (10 footers) 3-4 will work. When then mark all of locations, and at each location I take multiple waypoints over the area. That way if you're gps is off one day, you come thru the middle of the waypoints and you should find it on your fishfinder.

Remember this...The more tops in one location the easier it will be for someone else to find them on their fishfinder.