This past September, we needed bottles of champagne that popped open onstage, 2 per show. And they had to be non-alcoholic because the actors drank both bottles.
I found these bottles of
Sparkling Chardonnay Grape Juice at Trader Joe's. They're really cheap, non-alcoholic, and have plenty of bubbles. I'm not sure how much they'd overflow, but there's no harm in getting a couple of bottles as a test, shaking them, and opening them. Our local TJ's only had about 15 in stock, but they were really accommodating and took a large order from us that they got on their next truck delivery day that week.
I'll swear by these because they're cheap, taste good, and look like the real thing. They have a real champagne cork so they pop, too.