Dresser Style 90 Compression Fitting Torque

I am looking for torque values for Dresser Style 90 fittings and couplings. No luck on the Dresser website. We have 2", 1-1/2", and 1-1/4" fittings and couplings installed in a fluid system. I would also like to know if there is a torque tolerance range (+/-) for tightening these types of couplings and fittings. Thanks