I true my tires and round the edges then mount them up on the car. In the rear I take the pinion off and rotate the axle while the nozzle of a CA bottle is just touching the surface of the side wall. I tiny squeeze to get the glue flowing is all it takes. Capillary action with draw out the CA you need to coat the side wall. Start at the rim an spiral out to where you rounded the tire. All you need is a little bit. Your side wall should look matte black not shiny from the rim up to half of the radius where you rounded the tires.
If your side walls look shiny put them on the truer and sand off the CA and start over. Shiny side wall are too thick/hard and will crack and chunk in crashes. Matte black side wall are still flexible but they have a protective CA crust to reduce chunking that reduces traction and make the car nicer to drive.