Get everything as low to the frame as you can...bunks,rollers .etc....when the boat is at rest on the trailer you DON`T want to be setting on the rollers.....could damage the keel. The lower the boat is to start with is the less deep you have to go to launch. The front roller really is the only one that comes into play if you back it in till the rear of the boat is floating up. Float it off and back on. ideally you want to use the winch to pull it up the last couple of feet (using the roller to lift the front) and that will usually line it up on the bunks when you pull out.....use the guides to align the rear to the bunks.
I can`t stand clamp on rollers and bunks so once I had it all adjusted I welded the stuff in place and threw away the u-bolts and junk.
I`m sure a Master Backyard Engineer such as yourself will figure it out with style. !!!!!!
