Winch the boat on, which can be done on land and get the boat so the transom sits on the end of the rear rollers. Hopefully if the trailer is the right length you won't have too much room at the front. If the boat is too far foward so you can't turn the jockey wheel handle then move the boat back a bit. Adjust the height of the winch next.
Check the nose weight, with a disco and an idea postion of the P22 on the trailer I couldn't lift the nose of the trailer so it probably had a nose weight of 50 - 100 kgs depending on how much fuel was on board. If the nose weight is wrong you need to move the axles which means removing the boat. You might be able to do it with jacks and axle stands with the boat on the trailer but its a lot of weight and it would hurt if it went wrong and you are working underneath. A P22 will sit quite happily on the planning pad without falling over. It can be tripped to one side for cleaning and lifted back up with a small jack under the ledges on the side of the hull.
So assuming you are on dry land, using a large pulley block and rope use the trailer winch to pull the boat off the trailer onto flat dry land. Grass is good but if its concrete then flattended carboard boxes and carpet will protect the hull. Move both axles, you will have to guess but 6" steps won't be far out, adjust brake cables and winch P22 back onto trailer. Check nose weight, if still too much or too little boat off and more adjustment.
Once the boat is in the right position on the trailer and the nose weight is acceptable you can then think about the position of the rollers to see if moving them sideways helps to spread the load. Closer together means a higher boat and further apart means lower.
Properly set up and towed with a decent 4x4 towing won't be a problem. We have done 270 miles in a day without problems so worth taking some time and getting it nicely balanced.
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