AJ,this is a subject that I am all to familiar with. I go through this ritual every year with my 2 boats and quite a few others. I have accumulated a large supply of cement blocks,planking,and other blocking. Some of which always seem to migrate to other parts of the yard,but that is another story. I generally start by painting the whole bottom on the trailer. When that is completely dry I then place cement blocks in pairs at each corner of the transom,alternating them as I go up. I will then start jacking up the back of the boat just behind the keel until I get about 2 1/2 or so inches above the bunks. Then add a cross plank and wood blocking till I am firm against the bottom. Then I will let the jack down. I will repeat the same at the bow. I also will jam 2 2x4's midships (with rags at the top to protect the gelcoat) from under the rubrail to the ground,all the while checking after each step that the boat is stable before even attempting anything else. You can then paint under the bunks and keel. When the paint is completely dry you can let the boat down reversing the order in which you went up,bow down first and so on. For my main blocking I use standard cement blocks. I also have 4x4's,2x4's,and 1x4's cut to 16"long and wedges. I use a small roller,about 1 1/2" in diameter and about 6" long for all my bottom painting. And also be sure to use a wide block between the jack and the hull. I discovered early on that my bottom will flex too much for my liking,so I will only jack and block in structurally solid spots such as near the transom,forward near the bow or close to the keel. Sorry for being long winded. Above all,go slowly and be careful. I have been doing this for many years on many different boats without any problems whatsoever,but I am still very cautious. Anyway,this is all much simpler than it sounds. If you have any questions just ask. Good luck and have fun!!! Jeff