I started doing this a few years ago and thought that I should pass it along. When I move my trailer in the garage by hand I found the easiest way to move it is the following:
(1) lower tongue all the way to the lowest height
(2) lower the motor all the way down. (make sure you lower the tongue first)
(3) with the tongue all the way down and the motor all the way down the trailer should be pretty close to being centered on the axles.
(4) you will now be able to slide the tongue left and right w/o pulling your groin
(5) ensure that you chock your wheels to the front, so the boat doesn't roll frwd, just be sure that you remove them befre you try pivoting the trailer
(6) if you really feel spontanous place some bounce dryer sheets under the wheels and that will even make it even easier to move
I have been moving my trailer this way for years and it just seems a whole lot easier than having the motor trimmed up and tongue height raised up.