Ian I paint on the trailer every year but I also have rollers. I hook the trailer up to my truck and then keep the winch strap on and push the boat back a few feet. Paint where I can access then jack the boat up to access where I missed. I built a block that’s is in the same shape of the bottom of my boat so that it’s distributing weight throughout not just on the keel. I use the same block to build the frame for when I cover the boat every winter. Pm me if you wanna see pics I can’t post from my phone. Good luck Posted from my iPhone/Mobile device