I'm 6' 7" and ride a 63 cm CAAD 9-5. I had a pro bike fit done 2 seasons ago and have been overall satisfied with the fit considering how undersized the bike is for me. I have a pretty substantial seat to handlebar drop. My seat is about shot and it's the seat that came with the bike. In selecting a new seat what do I need to keep in mind in choosing the correct saddle?