Well, I don't have a definitive answer to your question, but I have something that you can think about as you experiment. Usually a green bowl that has been roughed out is left 1" to 1 1/2" thick. Additionally, and perhaps more importantly, almost all the exposed surfaces are end grain. There's a little long grain on the sides and bottom, but not much. PEG was developed with the idea that it could be used to dimensionally stabilize lumber. Experiments, however, showed that while it would penetrate end grain to some extent, it would not penetrate the long grain very much. It has never found a commercial application matching the expectations of those who began the research. Ed Moulthrop (and his sons) from Atlanta Ga. used PEG to dimensionally stabilize their bowls. Ed would turn a bowl from a bolt of a tree, turning right into the end grain and including the heart center (pith) to about 1 1/2" or 2" of thickness, then immerse it in PEG, then re-turn. He developed a finish to use on these bowls which he would never discuss except to say that none of the other finishes he tried would give satisfactory results on PEG treated wood. I don't remember how long he would keep them in the PEG. I did a workshop with him quite a few years ago. He was a very interesting man and I learned a lot, but I wasn't interested in duplicating his methods. He would tell you all he knew about wood, lathes (he designed and built his own), and turning, but he wouldn't talk much about his finish. PEG is chemically related to DNA. One of our members is a chemist, and perhaps will give us more information on that. Your wallet is probably all that will be hurt if you try this though.