The bow in the neck is required. A good rule of thumb is fret the 1st and
the 22nd fret on the 1st string and the clearance at the 7th fret should be
0.015" - 0.020".
If it is between these numbers it is fine... if not see your repairman. You
can adjust the truss rod on your own BUT BEWARE if you shear the truss rod
your banjo neck is as they say TOAST!!!
Thanks to Chris Wyvill for this info!