100% agree with Jarrad.Surface preperation is not as important with Hammer finish,as it covers minor imperfections with minimum coats.Sandblasted or new surfaces do not require primer.Hammertone finishes of the era/period your Victa was made did not use an undercoat.Spray tin hammer finish in my opinon requires more coats and does not offer quite as good a patina.Best results are achieved by a gun.Because of its consistency,hammer finish if sprayed correctly gives the appearance and depth that a clear coat offers anyway.Did you make a colour choice yet Luvpsi?