My manual for my 20HP Honda recommends putting the motor in the drive position (all the way down) when trailering if you have the clearance. I do so that is the way I drive with it. I did use a transom saver at first (I have the electric trim on mine) but wasn't happy with it still moving around back there. My boat is so light that I get a lot of bounce in my trailer going down the highway. I got a "transom saver" that basically is a dense plastic block that fits around the hydraulic shaft and I trim the motor down onto it if I'm going over speed bumps or backing around curves. I used to put that in once I got to the lake because of the speed bumps but I have found that I have enough clearance that I don't need to do that anymore.