You can still use screw tops but you can't use a hand capper to do so. You'll need a bench capper. The reason is the lip where the hand capper grabs on will not be strong or thick enough to clamp to and will result in either the bottle breaking or more likely the capper not able to apply proper pressure.
With that said, go to your local pub and befriend the barkeep with a couple nights of healthy tipping, then ask him to set aside all the Sam Adams bottles he can muster. Pick them up daily so they don't pile up at the bar and after a couple weeks you'll be swimming in good cappable bottles where the labels peel right off.