Ca. Piece rate 32/12 pitch

What to pay a employee/ shingler in norcal per sq the roof is a 32/12 mansard

Not really a per sq price. A sq price would depend on how the job is setup, is it scaffolded?. How tall is the mansard, a 6’mansard is much easier to shingle than a 12’ mansard.

What MPA said. You certainly can’t pay fairly by the square.