I do not think it is a good idea to mount 3 or even 4 blade props on the Q500. Usually they are less efficient, louder and consume more power. In the best case you will only lose flight time and gain noise. In the worst case you will burn your motors or ESCs.
More blades are only useful when you have a limited space but large amounts of power, which cannot be used otherwise. The Q500 has already a good setup which I would not change too much.