Is it time to review the wig-wag tank height check?
Because centrifugal force - CF -acts straight out, gravity straight down and maneuvering g loads at right angles to the wingspan direction, we can pre-set tank height so that the engine run doesn't change upright and inverted. We can simulate the direction of loads on the fuel, but not the actual load values, unless we are flying alongside the model...
The angle of "gravity direction" the fuel feels in flight results from CF, gravity and maneuvering forces. In level flight, CF is about 3g as a rough rule of thumb. So, in level flight, the fuel acts as if the force on it is at the direction of the diagonal of a rectangle with the top edge 3 units long and the vertical side edge 1 unit high. In upright flight, the diagonal points out and "down" (towards the wheels. In inverted flight the diagonal still points the same direction, but since the model is upside down it now points out and "up" (towards the 'cockpit.')
(This covers maneuver loads, too, since lift IS at right angles to the wingspan when the model is level, inverted or upright.)
How?
Start the engine. Set it a bit rich so you can hear it go leaner if the tank is too low, or richer if it is too high.
Hold the model with the fuselage centerline level, and roll the wings so the outboard panel is straight down. This is just a convenient mid-point between the rolled positions you'll use next. Note the sound, or tach the RPM, in this position.
Keeping the uselage centerline level, roll the wings to about 45°, say "cockpit up." Note any RPM or run change.
With the fuselage centerline still level, roll the wings to the other 45° position ( say "cockpit down"). Note RPM or run change.
Think about this. It goes leaner in the roll position where the tank is too low, and the engine has to draw fuel "uphill." To prove that, notice that it goes richer in the other rolled position where the fuel is being "poured downhill" to the NVA.
Repeat the roll position tests until you are sure which way the tank is 'off' from where it should be. A quick, safe way to stop the engine is to point it nose down, outboard wing up.
Shift the tank to reduce the RPM (or run) difference between the rolled positions. Run the wig-wag test again.
Two or three times through this procedure should settle the tank where there is NO RPM/sound change at the ~45° rolled positions. The model should now be safe for first flights without flameout or floodout. ...Should be very close to the final position where upright and inverted, and inside and outside runs are identical. But, like everything else about model airplanes, there may be some final tweaking to nail it.