Boat jacks work nicely, and you would not be “installing” them. They are portable. When I had a C22, I used a cradle for the stern and boatjacks for the bow. I lowered the trailer jack to the ground, slid the cradle under the stern, and raised the trailer jack. This effectively held the boat between the bow roller and the cradle. Next, I placed a flat boat jack stand on each side of the bow outside the width of the trailer. I then slid a 10’ 6x6 timber under the bow and put it on the jacks. I used the jacks to lift the bow. The I removed the trailer. I then supported the boat with stands. I don’t think I would do this with any boat larger than that.