My learning experience was when I was asked to make some bikes for a local track program. They wanted really small bikes (46-47cm) but the kids didn't like the current bikes with 26" 'Kids' wheels, so the velodrome insisted on 700c. The compromises were significant and I have heard from adults that they ride funny. Any time a 6 footer rides a size 47cm track bike, they are likely going to say it rides funny but, the point remains there were too many compromises and I learned my lesson. Go with 650b wheels. There are many great options for wheels and tires for 650b so no reason to not use that and gain a couple cm of clearance.