I cut from ply a curve that I use to bend the GG track. To get the final radii I just re-bend to the exact radii I have drawn on the roadbed. Bending GG is NO where near the horror story I always heard. In fact it was too easy....figured I was doing something wrong.
I may be contact you in the next few months. Buying the O-72 ,but bending the Std size to an 80 Radii.