To set a boat off a trailer onto blocks is pretty straight forward with either bunks or rollers. Its easiest with 2 jacks and some concrete blocks and 3 small pieces of 2x wood.
You jack up both rear corners and stack the blocks under each transom corner with the wood between the hull and top block.
You then remove the jacks and place on under the center keel up front as far forward from the trailer cross member as possible and jack that up,
then you pull the trailer out from under til the jack nears the member..
then take the other jack and place it as far forward from the 1st jack and jack it up, then remove the 1st jack and move it forward again.......wash, rinse, repeat til you can set a final front set of blocks and wood, while pulling the trailer all the way out.
Getting it back on the trailer is the same in reverse.