Jack,
To reload the trailer, I set the trailer's wheels about 2-3 feet from the water's edge. I then walk my floating H16 forward (using the dolphin striker bar) until the bow tips are just on top of the trailer's rear rollers. From there, I loop the trailer's 2"x25' winch strap/hook around the cat's front cross bar next to the mast step. I now can manually winch the boat up onto the trailer. I usually pause this process when the transoms are just barely out of the water. With the hulls now at a steep angle, I can remove the hull drain plugs and drain any water out of the hulls. Next, you can continue winching the cat forward and guide the bows so they gently come down on the trailer's front rollers and then continue winching until you have the cat in the proper place on your trailer.
Leaving the winch strap attached to your front cross bar will also prevent the boat from rolling backwards on the trailer when driving, etc.
I used to lift the boat from the rear cross bar, but my tramp made it too hard to see where my front rollers were in relation to the bows.
If you want to take your boat off the trailer at home, make sure you either have the trailer connected to your vehicle or have someone stand on the trailer tongue so it will not pop up while you are pulling the boat off onto the grass. You may also want to take your rudders off before you pull your boat off it's trailer onto the grass otherwise there will be a lot of stress on the rudder hardware (since the rudders will only go up so far).