I would definetely spackle. If you don’t, chances are you will get bubbles and pin air in the lam because of the uneaveness in this area which may extend wider than what you can cover with a normal pin line.
IDap fast n final is a vinylester filler made for interior & exterior applications. Most spackle type products are made for interior only applications. fast & final sticks better after its dried.
After you spackle & sand, make sure you have all the dust vac’d up. Then spray a clear coat around the area you are going to spray. Next lay your tape down, but don’t mash it to the foam like a poly blank. Next fog on some more clear coat…the clear coat will seal the tape edge, and keep it from bleeding. Now shoot your color and pull tape. EPS is a pain in the ass to color. That why EPS boards usually come in a wide varity of white! Also most color is done after the hot coat, and usually only on the deck. But your now figuring out all that!
I always re-spackle those places where the tape pulled up beads. If you don’t, nine times out of ten it will blow air in those spots. Not worth the risk…
The way to avoid any issues with tape on foam is to do your colour on the sanded filler coat. (Just as you will your pinstripe over the pulled beads…)
Any blade cuts directly on EPS can give you issues, as will attempting to paint with a less adhesive tape. (Nothing worse than your tape-work lifting mid-spray…)
Cutlaps on polys do the same thing…just tiny ragged line, and so the traditional pinstripe was developed to cover it.
If its only a little bit you could get it on the run in the lam, but take the board from warm to cooling as you work it. Spackle is always a hassle on eps if you need to feather it in against foam, so if you have to go there, blade it down flush as best possible.