Like I have always said here, why on earth would someone NOT lean out the low end needle ?
the engine manufacturers don't have ESP, thay can't predict prop sizes and atmospheric conditions...YOU have to do the fine tuning.....You WILL NOT, CAN NOT damage an engine by adjusting the needles on the ground, then flying the plane..If it idles on the ground and transitions well it needs to be adjusted until it doesn't, then opened up until it does...Too rich is as bad as too lean, especially with CD ignition..A too rich lower end setting will cause the engine to bog when the throttle is opened..The ignition HAS to change timing according to crankshaft rpm..If a rich condition causes slow transition the ignition can't advance properly...
Ignitions don't react until the rpm changes, no matter who made the ignition in the first place...
There's nothing in a Walbro carb that could possibly react to something as slight as a change in attitude.....The problem, if there is one, is not from a properly adjusted Walbro....