Rotor Chord position is variable, we get helicopters in from all parts of the country for service and the auto RPM's are adjusted for the elevation at which the aircraft is to be routinely flown.
For example during maintenance I ask the mechanics to adjust full down collective pitch angle to maintain proper RPM here in Mexico City which is at 7500FT, and then the customer takes the helicopter the helicopter to sea level, an tests his auto RPM, the helicopter is going to have trouble maintaining proper auto RPM's with anything but full down collective, and if he tries it when he's at low weight he might not even get above 90% NR, so he's going to have to adjust his full down collective pitch even lower.
So you see its a variable thing depending on different factors, but looking at it from the ground it looks like 2or3 degrees negative at the tips when collective is full down.
Thanks for posting your models, that looks pretty impressive!