Well PS is the last line of defence. There is actually something better than the PS healing tool. It's the "freehand draw" in CCD Stack. Then Impute Rejected Pixels prior to stacking. That's what I've been doing. My problem is that Sigma Reject on a stack will detect cosmic rays because they come and go but won't detect a slow moving object if the signal overlaps slightly from one frame to the other. It will treat it as a star "bouncing" in bad seeing and will keep a faint signal. So you end up with a faint line. Dithering doesn't resolve the issue because the position is relative to the stars.
Just wondering what other CCD Stack users do.