A lot of engines, 2 & 4 stroke, aren't necessarily at half throttle when you are at half stick. You can program throttle expo to make your half stick position become half throttle on the engine.

I'm not sure about leaning your engine just for more vertical power. You should set it like OS outlines in the manual, which is probably a few hundred RPMs on the rich side of peak. You could find more vertical by lowering the pitch of your prop.