It's always a shame when someone asks an interesting question and gets no response. I favor the 1-into-4 '69-'70 carbs for a lot of real-world reasons: they're simple; they suit the SOHC4 well in sizes up to 900cc in real world situations (not just a really great top end while matched with spotty starting, overcomplicated internals, intractable low end, etc...) and all the parts you need are available. Also, the '69-'70 throttle is much quicker and more linear without being extremely quick. But that's just my take. I'm not an expert. Then again, none of them replied...
Spirit