In reply to ri6625:
I did 107 laps on an auto belay at notts. I subtracted 7ft for my height and the last holds being shy of the top - but also because it made 27ft 20ft which makes the maths easier! I did all the climbs on lower grade route (5s from memory).
On F6a and bs my best dived to 60 something - can't remember exact but lots less so I think the grades of the routes make a huge difference.