So why does IVO recommend the 2 blade medium prop for the 3:1 gearbox?

I called them and they really didn't give me an answer, I'm not sure if the gentleman I talked to even knew.

I then asked if I could add a 3rd blade for climb and he said sure.

I then asked what diameter he recommended, he told me 72-74"

Now I have read that the 2 blade prop sucks with the 582, and that the 582 has a hard time turning the 3 blade 70" + props.