I've got some spot repairs that need done along the strakes and a few spots on the bottom of my boat. What is the best thing to use to thicken the gel into a paste or putty? I thought about West systems 404 but I would think it would be tough to buff out when done. Cabosil?

Cabosil

just do multi pass's to build it up...cabosil works but if not mixed properly the gel will turn to powder and leave pin holes and cavities..you can also fill the scratch with 3m filler if its too deep then use your fingr to wipe off the access and smooth it out then litely scuff it and go over it with gelcoat,,also you can go ovet the gelcoat with a bondo spreader and some wax paper so you wont need to mix wax in it then wetsand and buff it..leave the wax paper on until the gel cures..