Good feedback so far. Just to clarify: I'm just trying to do spot
repairs, [at least right now for this season]. The gel is chipping
off in small pieces the size of a, grain of rice, fingernail clipping
to the size of a full fingernail/small coin. So I don't think
spraying makes sense. Getting sandpaper into the spot is difficult
because some areas are no wider than they are deep, and you have to be
careful to not scratch the main clear part of the canopy that is
directly adjacent.

The chips are the full thickness / single layer of gel. It is about
as thick as 2-3 pieces of paper.

Maybe I should consider next year having it all stripped down, all the
gel removed and a totally redone, right now I just need to get patched
for the spring.

If I put primer on the plexiglass, would gelcoat adhere to a layer of
paint primer?

Chris