Ghibli Oil Pressure Sender Torque

Does anyone have a spec on how much to torque the oil pressure sender into the block on a late Ghibli SS. This car uses the low oil pressure light sender to hold the electric sender for the gauge via a banjo on the gauge sender. The entire unit is held to the block by the light sender and seals with copper washers. The thread size is 12 x 1.5. It needs enough torque to seal the copper washers against the oi pressure , but not so much as to risk damaging the threads in the aluminum block. Appreciate your information.