I always heard dual plane tend to need larger carbs, maybe not that larger though.
Like PRH all it tells us is those two engines like it.
Too me I see carbs as a necessary restriction, you want the least restriction that is able to perform as needed (needed can very widely depending on application, goals etc..)
Sort of but not really --LOL. This is a major hint right here>>> The best running street engines will produce about -1.5" hg @ WOT AND move close to the same amount of CFM as the carb is rated for.
As has already been stated if you are looking for the least restrictive carb and pull -.5" hg for that last 3hp it will not drive/perform nearly as well as the above example. J.Rob