Canvas sizing before covering with ground

Hi,
I'm familiar with the issues regarding rabbit skin glue, expansion and contraction etc... so I've decided to try PVA & Gamblin oil ground or acrylic gesso alone. My question is this:

How far back has acrylic gesso stood the test of time. How do we know it isn't going to peel off the canvas in fifty or so years? Does anyone here use PVA as a sizing for canvas? Have you used it on hemp or linen? If so, how does it compare to rabbit skin glue.

My other questions are regarding sizing the canvas. I was thinking (this gets me into trouble sometimes) about sizing and it's purpose. The sizing is used to seal the fibers, stiffen the flexible surface for painting and provide a base for the paint to bond with right? How would carpenters glue work as a sizing medium? It's porous, somewhat sandable, slightly flexible but mostly rigid. It's made of a combination of natural and synthetic resins (mostly PVA) and it's also made to not absorb water or expand or contract. It seems like the perfect fabric sizing! Does anyone have any experience or insight into using waterproof carpenters glue as a sizing medium? How well would this serve such a purpose and how long would it last? Also, I wonder how acidic it is... I'll be sizing some beautiful and expensive hemp canvas and I'd hate to ruin it's neutral properties or it's mildew resistance by experimenting. Most glues today are made from PVA and I have to wonder if PVA size isn't just bottled, relabeled and marked up wood glue.

Thanks,
~Justin

FYI:
Also, I got a pretty good deal on hemp canvas at 10.00 a yard (11 oz) at www.HempTraders.com. It's a little larger weave than cotton duck but the weave is flat and smooth. I also found another wholesale source that's a bit cheaper but you'd have to buy in larger quantities (>10 yds). In case you are unfamiliar with hemp it has the same mildew and pest resistance as linen and it's also a good neutral ground so it's as acid free as linen (No, you can't get high off of it). There are new advances in technology concerning the processing of hemp so it is much softer and finer weave than it was even a few years ago. It's twice the cost of cotton but one third to one half the cost of linen. It's not as fine a weave as the finest linen so it would not suit all painting styles unfortunately. There might be finer weaves but I havn't found them yet.