I you go the sander route, I recommend a 6" sander vs. a 5" The extra 1" increases your sanding area by 44%. I used a Ridgid 6" sander connected to my Shop Vac to take the hull to nearly bare glass. Now, I use it to prep for paint
every spring. Takes 3 hours for a 38' hull.
6" Random Orbit Sander - RIDGID Professional Tools
I used 60 grit followed by 120 for the stripping as detailed below:
Victoria Bottom Stripping & Fairing