For some years there have been some posts on different forums where both drew and i have put in som thoughts on the subject of "finding the right old Holley color" and others to for that matter whit more knowledge. 1 What is the right "Holley color"?  the older late -50 to earley-60 carbs i renovates is clearly to the goldish look. Some later -60 High Performance carbs are looking more greenish yes but its hard to tell what they looked 50 years ago.
Like Drew says,  i don't know what color this particular casting will turn out when dryed and cured.
they all com out slightly different depends on the metal in the casting and the corrodes  over the years and even the contaminating to the metal deep in the pours. Even after cleaning, ultrasound, blasting and chemical treatment it will never bee the same as the castings came fresh and shiny straight from the foundry.
Most of my carbs come out looking to the green-grey look.
I think one must have several different chromate baths to ply with fore the same carb and just try and error to find a specific color and every try has to sitt for at least 2 days to cure. You can see the problem now to say " no problemo" i can color you carbs to the color what ever you think is the right color for your Holleys. I have never had a customer yet to complain about the color.
This question has been disgust for carters and rochester carbs too and the answer was that they used what ever color that was in "the run" fore the moment, mostly att the gooldish look.
 
 

The Idle solenoid was used on several HP cars OEM style without AC. Like BOSS 429 , HEMI426

To entirely remove the divider is a good way to get distribution problems. Its a known issue among smb ford historic road racers and some have got so bad distribution problems that they scored a cylinder in there seeking for the last ones.

The Nitril //  BUNA-N is more resistant to Alcohol than the Viton material on the other hand Viton is more recistant to fuel than the Nitril. BLP has gone back to BUNA material on the N&S orings.
Last time i got orings from Mcmastercarr i ordered the BUNA material. so far so good just a little to short time to really say.

For what ever reason Holley made there choice to calibrate the truck avenger carbs that way those carbs don't function properly on a regular car 200 ore 500 Hp dosent matter. It will take a skillful person like Drew to rework it to function on a car ore even a truck what that matters.
Get another carb or rework it.

The idea with the Main Air Bleed is to lean out the fuel curve in the upper part of the curve because the signal to the booster increases whit air flow in a not linear path so the carb will turn overly rich otherwise.

https://youtu.be/dQhVGYF6-ho
Dousent get any cooler than this avesom -67 Tunnelport fastback. Even if there is modern alternatives of induction choices this is hard to beat.