Do they need to be wine bottle shaped?

If swingtops that are shaped for beer work for you, find a local independent bar or pub. Stop by before opening and ask if they’d mind saving their swingtops for you.

When I did this, the answer “Sure, just bring one back for me with your first brew.” More, they already had a box of them set aside.

Grolsch bottles are by far the most common and will be 450ml, green, and with a raised glass patterning. Those are the most common. 9 ounce bottles from small commercial breweries will be smooth clear or brown with paper labels you’ll want to soak off, and they’ll have significantly fewer of these.