Hope this helps someone out. FYI Greenback not as good as STK C90 in my MKIV widebody combo. The green back sounds sweeter, nicer highs and a lot better sounding mids,but, the bass is a problem, IMHO. The GB can't handle the bass and the bass becomes lose and loses a lot of punch. With the stk C90 speaker, it feels like you have a bass player, playing a long with you, compared to the GB. Also the C90 is louder with more punch and highs, still the GB sounds less harsh, and more vintage woody sounding. I think the new Celestion alnico gold might be a good match. That will be for someone else to try, to much money for me. I was only using the GB on tweed power in class A. At full power the speaker would not last to long IMHO. So the gb is a sweeter nicer sounding speaker except that it can't handle the bass. I switched back to the stk speaker, because over all it works the best for everything. Mesa knows best