Where I once worked they did a lot of hull refinishing. I didn't pay
too much attention, but I will stop there tomorrow and get answers to
your questions. Gelcoat with wax, sprayed on will harden but it won't
be smooth as it doesn't 'flow'. I am pretty sure they used another name
brand additive,( not wax, styrene or acetone), that helped the gelcoat
flow to the point that it was a vast improvement over straight gelcoat
though not quite as smooth as paint or Imron,etc. How much of an area
do you have to refinish?