Only just seen these last few replies.
If you knew how much I've had to sand recently (after full rewire and tons of plastered chases) you'd understand why I wanted to avoid any more of it! Not just the time it takes, but the mess - however if it's just a light sand, and can do it wet, then maybe it just has to be done. Have bookmarked those contoured sanding pads
re. the open weave abranet - have been using these with a Mirka "handy sander" (connected to a Henry) for sanding large areas of plaster - have found them pretty effect at containing dust. But for door frames, the "handy sander" is too large for the small surfaces and angles etc - but is there an abranet/mirka product that would work for this?
And if I do sand - no need for the Zinsser 123, right? Just sand, primer, overcoat?