Keep nagging! You are one of the biggest carb gurus I know. I'm only into basics101. Fuel goes in here, air comes in there kinda thing. The shop I use is good, but they don't know everything. I run a real old setup and they are not well versed and we did what we could with the knowledge we had. Throw a single carb and they can dial it in. With only one flow meter per carb you can't really tell which end is doing what. We were just guessing.
6 years ago the local roundy round carb guru helped get the two set as close as possible. One was eating more fuel than the other, like now. We blueprinted the air bleeds, compared metering plates,etc to get them as close as possible.
We knew they were different body numbers, but didn't know the differences.
Through jetting and drilling the secondary plates, we were able to flatten the a/f curve. It pulls the same through the entire rpm band. Though the front carb(-2) still does not use the same amount of fuel as the back(-4). The front carb fluctuates slightly about 5k rpm. Then recovers flow rate again. The rear pulls smoothly up through. We just figure that is from the design of the intake.
The HP curve has a slight dip, about the same rpm as that front carb drops. Don't have those sheets in front of me to confirm. I'll take any input I can get. I don't plan on making any changes, I'm just going to run it for now. It's been that way for 6 years, and has run great overall.