I couldn't tell the difference between the two rear profiles. Going back to 50 next time.
Bought mine from Jake Wilson. Price was the same, whether 55 or 50.
I'm about 3 years from "final" retirement. (Retired once already.) When that happens, Mrs. E and I are gonna do a day trip or two and get back what we lost when we moved from Utah -- the canyons in the Wasatch are a helluva lot more fun than the MS Delta. At that time I was riding a Honda 919 and the peg-scraping thing was exhilarating. The OEM tires on that bike were Crapstones, IIRC, but they didn't seem nearly as squirrelly as these on the Connie.
I'm older now and I don't bounce as well as I did, so I can afford to let up some.
I do believe in good, solid, rubber but the profile doesn't matter so much. The Crapstones on the Connie scare the hell out of me.