What are the best or most proper glove to use for heavy bag training? I currently use Century gloves that I used for kick-boxing training. Are these sufficient for bag training?
With smaller bag gloves your fist is more natural in the glove, the surface is flatter and better for hitting a heavy bag. I find there is less chance of injury. training gloves are definitely better than actual fight gloves, but if you decide to use your 16 once gloves to spar you do not want to destroy them on a heavy bag. Some gyms have a lot of bags, at my gym we have 2 real old good leather ones that are very heavy but they also are taped up. Other canvas bags are rough and can do a bit of damage to your gloves.
I think if you can afford it bag gloves for the heavy bag, training gloves 16 oz for sparring, and fight gloves for competition is the way to go. I know you are only interested in training, the 16 oz gloves I would save for drills with a partner.