To my knowledge, the system for attaching Shrader valves to tubes hasn't changed, and they're not unusually prone to the bonding issue I described. However, all my bikes are PV so I haven't looked closely at SV tubes since I stopped selling tubes in 2008.

I'd tell you to go to Tru-Value for O-rings, but I don't think they're in Athens. If you want I can get a bunch and stick them in an air mail letter. The letter postage is about $1.00, and I think the O-rings are about a dime or so. BTW you might find them locally, since the size isn't critical. Bring a valve from a dead tube (or a new tune) and but the smallest ring that's a snug fit on the valve stem. The ones I use are approximately 5mmID, 8mm OD eyeball measurement.