I think your ratio's are off. When using layup resin one ounce of resin would use 10 drops of hardner. I would assume that gelcoat would be a similar property. Pledge in the spray can is a great air inhibitor and readily available.
I agree. The number that comes to mind is 12 drops of hardener per ounce for polyester resin. I've had good results using the west marine finish gelcoat with wax in the formula. Mixing throughly is also important. Once you think you've mixed it enough, mix it some more.
sm
