If you are just doing a bottom paint removal
and not taking off the gelcoat
due to blisters
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...