Hello all I was talking to my local SW dealer about my issue of the bad plaster. He suggested to sand down the really rough spots and prime the entire wall with a high build primer. He mentioned that I could use a thick 3/4" nap roller to apply the high build primer even though they are usually put on with a sprayer. I tried a small area that was really bad and with a good sanding and regular primer it looks a lot better. I think the high build would look even better if I can apply it correctly with a roller. My first question would be has anyone ever applied a high build primer with a roller and if so do you have any suggestions? Second is does anyone have a primer they would suggest to cover a dark plum semi smooth wall to be painted in a light blue? Kilz Oil, latex, Zinser? SW?