That is one good lookin’ uni! Your description of the frame making procedure sound very familiar 
:
Where did you locate the crown?
As far as mounting on a larger wheel goes, I start with the pedals at 6 and 12 o’clock. Place one foot on the lower pedal and push off with the other foot to get the uni rolling. That way the other pedal has reached the 2-3 o’clock position as my other foot is planted on it, giving optimum leverage to get things moving.
Great job:D