Actually I do use Gamblin PVA for sizing. I got this from Jim Larimer over at Hybridphoto. We had a discussion about it a few months ago. I use it diluted 1:2 with water. I have not noticed a difference between that and gelatin/formalin sizing in terms of gloss. The PVA soaks right in with no real noticeable effect on the sheen of the paper. Do you use it full strength?