Your WUR range is already on the rich side. Lower pressure = rich, so 3.4 is at the rich end hot where as 3.8 would be the leaner side (hot).

Sounds like your adjustment simply isn't right. Demands will be different from stone cold to even only a minute running. The AAV will have started closing, the WUR will have started leaning out the mixture (as rate is raising) so sounds like your base mixture (allen adjustment) was slightly too lean. Go slightly counter clockwise from where you are and try again. We're talking a fifth of a turn, not an entire rotation etc. The closer you get to it being right, the smaller the adjustments. Not on even the worst car I've had to set up have I had to go more than 2 turns in either direction - the fact you've been from end to end means you could be anywhere at the mo.