On the B200, as copilot, when PF, i spool up engines to max prop rpm with my hand on the back side of the throttles, then ask for "set max power", captain sets max torque and replies "max power set". That is my cue to remove my hand, he now manages power until climb power is set, including RTO.
When PNF, he spools the engine up to max prop rpm and then calls "set max power". I set max torque AND keep guarding the power levers until after climb power is set. Captain has his hand on top of the power levers until rotation, and only he can (normally) call stop.