First, what do your plugs look like? This can tell you a lot about which way to go.

How does the engine pull at WOT on an up-line?

"Sometimes" the needles can give the false impression of being lean by making the engine bog in mid-range (load up) and you think it is lean.

I would start by leaning the low till it won't transition when goosed to 1/3 throttle, then richen until it will with out hesitation and add just a tab more.
Now before flying and/or testing the "high" end, richen it a good bit. I like to start really rich on the high end then back down.
The low always affects the high and with this engine and carb combination it seem to be more pronounced than in others. I never run my large gas engines for more than a few seconds on the ground at WOT, I have seen too many people do damage this way because the did not realize how lean they had there engine.
Now you should be able to transition from idle to high with no hesitation. Make sure you are a hundred or two rich on the top end and you have good baffling.
Now fly a couple of gallons thru the engine and then do your final tweaking by how it responds in the air.