Bottle volume has nothing to do with carb level. Whether you're bottling in 32, 22, 16, or 12 oz bottles, the priming sugar is evenly distributed throughout the beer when you transfer it to your bottling bucket. The concentration of the beer/sugar solution is a constant. Now, what would affect carb level is the amount of headspace you leave in the bottle. That generally isn't a problem, however, beings that the bottling wand is designed leave the proper amount of headspace once the bottle is filled. Now, if you are one of those that uses either carbonation drops or puts priming sugar straight into the bottle, there are, I believe, too many chances of inconsistency, so I go with the priming sugar/boiling water method.