18 or 20 oz. gloves for sparring?

[Ivansmamma]

Most guys at the gyms i have been training at use 12oz för sparring. The biggest heavyweights use 14 or 16oz. I never even seen a pair of 18oz or heavier gloves at any gym i have been to. Is this a difference between Europe and America? Does Americans always go all out in sparring and cause of that needs the bigger gloves?

[PeterTheGreat]

You can just spar with 16 oz. gloves. How hard you guys are hitting each other is up to you.