A thin film of TotalBoat Topside Primer will self level sufficiently, but a thicker film won't dry properly and can be very gummy when sanded. This primer is intended to be applied in a thin film coating (requires 1-2 coats), and can be applied by brushing, rolling, or spraying. One thin coat is usually all you need, and you don't need to apply extra coats to achieve full hide.
The brush or roller you use is very important in obtaining the desired thin film thickness, which is 1-2 mils dry (3 mils wet).
Brush: Use a natural bristle brush, instead of a polyester bristle brush.
Roller: Use a 1/8" solvent-safe foam roller cover.
Use TotalBoat Special Brushing Thinner 100 to help with thin film application and self leveling for brushing or rolling; thin with xylene for spray application.
Do not add more than the recommended amount of thinner. Note that it may be necessary to thin the primer in warmer conditions in order to extend working time.
When brushing or rolling, thin 5-10% with TotalBoat Special Brushing Thinner 100.
When spraying, thin 15-20% with xylene. Before application, test the fan of spray, and spray at a speed that puts a sufficient amount of primer on the surface. If needed based on your environment conditions, adjust the percentage of thinner until the Topside Primer sprays evenly, with proper fan and atomization.