A 50/36 11-23 setup is very close to a traditional 53/39 12-25. A 39t inner is slightly higher gear inch wise than a 36t for the 3rd-6th positions (14 15 16 17 on 39t, 13 14 15 16 on 36t) but every other combo the 50/36 11-23 is higher. Were you planning on keeping the 11t to match up with a 53 outer?