I want to do the bottom of my 260 as well. There are some pictures in the owners resources section of this site showing how one fellow did it on the trailer.
I will probably use VC17 on mine, I used it on my last boat and was very happy with it for freshwater use and even had the boat in the Keys for 2 months and it worked well.
The problem with doing it on the trailer is that you will not be able to do a proper job on the center board and trunk, really need to have about 2 feet of space under the boat to remove it. It is probably also time to change the center board uphaul line and you need to lift the boat to do that anyways.
Also you need to be cautious in sanding the bottom of the hull to prevent future blister issues, do only very light sanding. If you ever will want to apply a barrier coat to this boat now would be the time to do it before any bottom paint has ever been applied.
I intend to use a cradle for a 270 to work on my boat this spring once the 270 is in the water. I will probably apply a barrier coat first then the VC17 and change the center board line as well, it will be easy to maintain the VC17 after that because it does not need any sanding to recoat it every few years, so I hope to do most of it on the trailer after that.
Let us know how you make out, Bob