Lean idle. Rich cruise.

LOL. That's the 'idle-eze' method that IIRC Bill Jones came up with and has posted in various places such as Speed-talk.
It's just one of several methods of allowing the primary throttles to be further closed at idle.
The first time I did it we did it the old school way, a hole in each primary throttle plate near the idle port. Then the transfer slot was more the way it should be at idle, but for that engine, it needed smaller IABs. Discovered that trying to leave that evening. So that was also my first lesson in using wire to reduce restrictions. Lots of fun, and sure didn't fully understand it right away, but it worked.

My suggestion is to map out the carb which sounds like you're already planning to do. I don't *think* there is anything inherently better or worse with the XP versus an AED. If you want someone to fixup a carb for your situation, then contact Tuner (if he'll do it) or Mark Whitner, or Thumper (Dominic).

As far as the 15 AFR on the meter, why is that a problem? Was it in 3rd gear? Was it full throttle? Or was it just brief shot from from low rpm in an easy gear? In which case some of what the meter is catching is pump shot (or lack of). Increasing throttle and load the engine will want leaner mixtures. The power valve only opens when the load is too high for the lean mix and needs go richer as load approaches maximum. Somewhere's between 8.5 and 10.5 In Hg will be when you're engine wants to go richer unless its really efficient at part throttle.

Anyway, if I didn't already post so in this thread, focus on the steady state stuff first. After that is good, then the pump shot can be figured out.
Get the idle and off idle pretty decent. When you can get to a track or dyno you can test the WOT jetting PVCR combo. Going smaller with the MAB and reducing the e-holes so there are less and smaller or three and much smaller will be flatter, and worst case, it will get richer near the top rather than leaner.

Yea I know some of what I post contradicts what the magazine writers and marketing guys say. I've learned the hard way they that they don't the principles or the history. I suspect there's a reason Andy didn't go through with the advice that was given to him in that thread. He and all the others in that racket know which side of their bread is buttered. They sell product. Guys like Tuner and Shrinker make race cars go fast and street cars run well.