If you can do a sub 6 hour 100 and a 28 minute training 10 on 72" you will easily be capable of 26 minute 10, realistically once you get used to pace judgement you should be looking at 24 minutes as a target.
I only rode a few 10's this year, fastest was a 27 (within 2 1/2 minutes of the winner on a crap course where few riders beat 24 minutes) with no aero kit and a 90inch gear. I've never averaged 19mph at Regent's s on that basis you have nothing to worry about.
If you can do a sub 6 hour 100 and a 28 minute training 10 on 72" you will easily be capable of 26 minute 10, realistically once you get used to pace judgement you should be looking at 24 minutes as a target.
I only rode a few 10's this year, fastest was a 27 (within 2 1/2 minutes of the winner on a crap course where few riders beat 24 minutes) with no aero kit and a 90inch gear. I've never averaged 19mph at Regent's s on that basis you have nothing to worry about.