Where standard weights are used, it's 196 lb for male adults with survival gear. Some client require the use of actual weights, in which case the average pax weight would be used for c of g calculations.
Aircraft like the 225, 92 and 332 generally don't have an issue with c of g, and standard loading configurations are used to avoid having to make such calculations. Smaller types such as the 76 and 155 are more critical and, commonly, a PDA or similar is used to do the calculations in flight.