Hmmm... The SUs are a constant velocity design, meaning the air valve opens only enough to maintain velocity through the ventuuri so I don't see the need for progressive linkage with several of these carbs. I don't think fuel economy would be better and you might get into an unstable / bog condition with progressive linkage used for agressive driving. Dunno. I would just hook them up all direct.
Likewise, a friend of mine tried a plenum on DCOE Webers with no improvement. I think a more conventional manifold is in order, with minimal plenum volume. Just my opinion - no real data.
