fsts2k - I don't have a trailer so I will use the "On the water" Calibration" . For what we do, I think that will be close enough. I will be taking it off and on to cover the boat. Eric includes "Sticky back Washer" things that protect the Windshield frame. I think these will be an easy guide for placement every time. Again, not going to be course exact, but I think it will be really fun to have something to make turns on open water. Eric was also super helpful, I sent him a couple of pictures to check my set up and he got right back with a couple of suggestions. Unfortunately, its going to be about 3 weeks before I get to use it. Its an expensive toy, but my wife and I will use it 4-5 times a week on the summer.