What if you were to apply the medium to a gel plate, then apply that to your paper containing the pastels? That would eliminate the need to scrape the medium over the pastels. I Don’t own any pastels so I can’t try it myself. It it worked it would be less fiddly which appeals to me.

I have had great success using the gel plate to apply various acrylic mediums to seal non-permanent mediums. You may get some chalk dust on the plate but that is easily wiped off. I just want to add that every time I saw you blow the dust off of your paper I could hear Sister Gabrielle’s voice from far too many years ago telling us to tap it off onto the desk and stop blowing it around the room or else someone was going to get wacked.