I think at best you have to go extremely lightly if at all. It's different than regular gel. If you sand past the clear coat you will be into the flake and in trouble. but I'm no expert. Someone will be along who knows.
'97 Prostar 190 - LT-1
Prior boats - 2009 X14, 2008 X14, 2005 197, 1988 Tristar 190, 1989 Prostar.