NOT the Metzelers, my friend! They suck . . . huge!
IMHO - the best combo is the 240/55R 16 Exedra Max rear and a 140/75R 17 front.
More circumference difference than that will likely fault your ABS.
I also ride a 2012 R3R. I have ran many and currently an Exedra Max rear. I now run a 150/70R17 Michelin Road 5 rear, run in reverse. It has the same circumference as a 140, but more meat on the road and the Road 5 is a superlative handling sport bike tire.