I have several door frames and architraves to paint. I’ve sanded back alot of the old gloss off the frames. There are some knots to treat. Although the MDF is primed I had to sand some bits back so that needs re priming. I have Zinnser BIN, should I spot prime the knots and use some kind of cheaper primer over everything, or just do the lot with BIN? Or something else? I’ll probably put dulux satinwood white on top, or maybe a water based paint with a similar sheen.