I haven't flown a 146 in five years, so my memory is undoubtedly faulty... the company I worked for had a quite mature fleet; the engines had suffered some abuse in their lives, and sometimes climbing, and then accelerating, over the Alps in summer was a protracted process. I think we were told not to exceed 800 degrees TGT in the cruise- I don't remember there being an MCT mode in the system, but I could be wrong about that.
Perhaps the 800 degree limit was a lower temperature than the absolute Max Continuous, intended to extend engine life?
Like banana head, sheer laziness made me use the TGT thumbwheel to change thrust settings in the cruise; my preferred mode, however, was only to control the master engine in this way- I don't remember the name of the mode, but it is definitely possible to control one engine's TGT, while slaving the other 3 to match its N1. Where possible, I would choose the hottest engine as master- that made it easy to ensure none of the engine TGTs exceeded 800 degrees.