I remember my race bike (A PAramount PDG ) had a 12-24 rear , 105 short cage derailleuer , and indexed fine with Gripshift. None of the climbs were big enough to justify a bigger cassette in my area - especially when you had a triple up front --- but 90% of the time, the granny was removed and i rode it as a double --- wish i had a pic of that setup for this thread .
Ahhhhh , to be 23 and in shape again