Rainy, I tried a little Golden Matte Medium diluted with water. I love this sizing for acrylic and oil painting, but it's got too much grit for my pen to battle. I have some Gamblin PVA size around here somewhere, but I think you're right and that going right to a gelatin size would be best. Look what I found online.
I think I'll make a stop at the grocery store tomorrow! LOL