The point being that in many cases where the centerline position is being looked at to cure engine running problems, there is usually something else at work causing the engine to run unreliably
Of course the needles has to be set ,Thats a given no matter what .
With your vast knowledge of engines and aircraft my 40 plus years don't stack up I guess?
Like I said run those tanks to high or low then do some inverted flying or KE, Spins and blenders and see how long things work for ya.
Do you take off with only 1/3 of a tank of fuel also ?
Read any engine Manual they tell you to set the tank up on the centerline of the carb or Spray bar.
When the tanks positioned properly I find theres no need to use only part of a tank to tune my engines ,they run the same inverted upright on there side and so on while in the air.