Never done it before or seen that setup in person, and I checked your photos and don't have any more if an idea...
But you sound desperate for some advice.

All I can say is get in there and figure it out, think what needs to happen, what you can make so it will, and try.
Might take a few versions but just try something, I bet it comes together as you go much nicer than you can think of all at once from the beginning, just try.

Grigg

P.S.
I did stay at a holiday inn night before last, and I have helped Cosmo with his dual carb linkage...
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=753600#Post753600



1951 GMC 250 in the Project Journals
1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-