If I do a light attack with one sword hitting the target it only procs of enchantment but if I do a heavy attack it procs both? If they are both enactments to increase weapon damage does it stack if I do a heavy?
The weapons can proc independently, so in a heavy attack both enchants can proc.
BUT...enchants apply status effects that don't stack, and have a cool down. You can't apply two fire effects at the same time. So you should use different enchants on the two weapons. Fire and frost can proc at the same time.