Saying you have to tune it running is just plain silly. In the air with differing cowl pressures and having the engine unloading in flight your fine tuned sitting on the ground engine isn't tuned for actual flying conditions. Any engine with more thrust than weight will never stop flying to match the setting you gave it on the ground. Also most of your flying will be at a throttle setting thats far less than what power is needed to hover. Only flying it will tell you if it will sag in an up line or if you have too much 4 cycling straight and level.
And ONLY flying it will tell you how hot it becomes if you run full throttle and for how long you can run full throttle before you cook something.