Dual quads versus big hammer!!!...

I don’t see any fundamental difference with this carb than an AVS, TQ, or Q-jet(there might be, but I don’t see it).
All of those have mechanical butterflies and spring loaded air doors.
I have always considered them to be “vacuum” secondary carbs, for lack of a better term.
It’s more like, secondary air flow “on demand”.
The air door opens only enough to satisfy the demand, to keep the velocity through the secondary barrels high.

I worked at a boat shop in the 80’s.
One of the models of small cruisers we sold came with a 305 with a q-jet.
These were pretty heavy boats that took a while to get up on plane.
At full song they were set up to turn about 4600rpm.
If you watched the secondary air valve in operation when going from low rpm to WOT, the valve would barely open at all(and it would slowly open up as the rpm went up).
If you pushed it open at that point, the boat would slow down, and never get up on plane.
If you loosened the spring tension on the door so it opened sooner, it took longer to get up on plane(too loose and it wouldn’t get up on plane at all).
At wot, at full speed(4600rpm) the air door was only open to about a 45* angle.
If you opened it up all the way, even with the motor already at full rpm...... the boat would slow down.
The factory setting of the door opening slowly, and not opening all the way at terminal rpm yielded the best performance in the boat (imagine that).

Even with the q-jet on my friends stocker...... we have the door set up with the spring tension pretty high.