The enchantment numbers are identical to that of the vision and mighty ring of which both enchantments last for 30 minutes. If no-one has tested this it's probably wise to assume this is the same @30 mins life on each enchantment until sum1 proves differently
doesnt that put it just barely in the lower TP gain per hit i think 445-495 is more tp gain than than 442 but idk the proper math for the non sword weapons