First point:
The maximum climb rate limitation on the Bell 407 is there because it was not possible to demonstrate static stability using takeoff power. It's a silly limitation and should be removed.
Second point:
There is no performance charts for this type of maneuver, and there are so many different techniques used that it's silly to say there is such a thing as a 'maximum performance takeoff'. One of my favorite rants!!
The article(s) in Vertical magazine discuss this at length. Anyone who wants copies should PM me.