What happens if you fill an air tank up to 100 psi? It sits there under pressure, stagnant in your words. If you open a dump valve you will have nearly instantaneous release of that air. The higher the pressure, the more forceful the release. The bigger scoop will trap more air and will build potentially higher pressures that will be used when the carb blades open more.
Unfortunately, I don't have "does and don'ts" to help you out because it is very complicated to analyze and there are too many variables. I think that field testing is probably your best bet. Don't make the scoop so large that it overcomes the power advantage by increasing the drag too much. Larger engines/carbs can use more air (duh) so they could use a little larger scoop. Getting cool air into the carb is just as important. The cooler the better (think inter cooler on a turbo engine).
It also seems to me that you would want to minimize the turbulence created while building air pressure with your scoop. The way to do that is to make the scoop more like a funnel, with smooth (albeit curved) sides that lead directly to the top of the carb. That way, all air that comes in is directly funneled into the carb in a laminar flow manner, without the creation of turbulence.
I haven,t worked in the engine field like IQ52 and others here have. They can probably give better advice based on their practical experiences.
