The average soda can makes gargantuan cuffs; I'm sure they fit a lot of big people, but they sure as heck don't fit me and most of the people I know. We drop our arms by our sides and they simply fall off.
I use certain Arizona iced tea and Red Bull cans, which are 7.5" around, and also Starbucks glass bottles, which are gently squared. (By that, I mean they are roundly squared.) (The corners are rounded.) (Can you picture it yet? I hope it makes sense.)
I look suspicious at the bodega, measuring beverage cans I don't intend to drink!
I can't imagine what you're doing to dent a soda can; do you mean when you're trying to get the bracelet off? I wrap my cans/bottles in wax paper so the bracelets slide off.
I hope this helps,