Preventing Primer From Showing at Molding Edges

In a recent post, I mentioned how when there’s a strong contrast between the color of the woodwork and the primer, you don’t want any primer peeking out between the wallpaper and the molding. So when rolling on the primer, I cut in with an angled trim brush along the molding. But I’ll pull back just a tad, leaving a 1/16″ or 1/8″ gap or so, so the white primer doesn’t actually touch the woodwork.
This prevents any of the primer from showing after the wallpaper goes up.
Wallpaper paste doesn’t adhere well to glossy paint as is used on moldings, but this teeny bit of of a gap won’t be enough to cause adhesion worries.