The Stage ribbon is not a true ribbon, it is aluminum in mylar like the BG's ect. The high output versions actually require fan cooling to keep them from melting. A true ribbon's voice coil is aluminum, with those you need to worry about stretching or ripping them. Best to use a steep crossover network (or biamp like I do.) Replacement ribbons for the ESG's are $10.00 US and easy to replace. I stretched a pair using a first order passive network crossed at IK.
The horn loaded versions of the Stage ribbon are non-linear and not as extended as the non-loaded version and are not as good as a good true ribbon like the Raven or ESg for accurate music reproduction. Those are better suited for a substitute in a PA system where you need controlled dispersion and aren't real critical about accuracy.
Do you have a distortion graph for both the Raven and the Esg?