Every painter uses glasso putty nothing wrong, but the most important part is denting, better the denting better the quality of paint. After putty is applied tell him to sand it using 320 and then 220 sand paper till all the excess putty is taken off the body. Then a normal astar is applied to check the lines and to see if any dent is left. Then astar is also sanded and then deco putty is applied which is again wet sanded.
After this tell him to apply hardener primer which is also then sanded using 1000,1500 and 2000 sand paper. This should make the base as smooth as possible and eliminate any defects or lines. Then base coat is applied which is also sanded and then at the last clear coat is applied.
