Paul, I'm more of a wannabe mando player, but even in my experience, the volume difference between different instruments is enormous. Cara (AKA The Potato Orchestra) boast the quietest (but beautiful Fylde) and the loudest (blood from ears Serbian affair) mandos, but it is ironed out by the PA.

My suggestion is that you tape the session, and then judge your volume against the ensemble.

Skipjack