If you are just doing a bottom
paint removal and not taking off the
gelcoat due to
blisters,
sanding is the way to go. Should be one day job to tent it off, sand it out with a softpad, and cleanup. Setup and cleanup takes too long with sandblasting, unless you are comparing it to a peeler.
Pay a pro to do it, unless you want to buy a fullface and 7" softpad setup so you can do it yourself next time. There's a big
learning curve on proper softpad
sanding too. Basically it's all in how you feather the trigger...