Tom I am not so sure about "Better Response" compared to CV carbs I do think because CV carbs feel smoother like Fuel Injection does they may not feel as Punchy.
It is amazing when properly tuning CV carbs and getting the low and high speed air correction right just how much power they can make, Often more than FCR carbs.

On a side note but also relevant, With Nissan Datsun HItachi SU type carbs Fuel level is vital to correct mixture, Too high and they go really rich and of course the opposite also applies, just a 1mm change can see Air Fuel Mixtures go from 12>1 to 15>1 at low to mid speed ranges.

FCR carbs unless you run something like Factory Pro modified Needle Jets really are a MotoCross On-Off sort of carb fueling wise, Fine for the race track maybe not so nice on the road in downtown Las Vegas Traffic.
The Issue with FCR carbs is in fact poor emulsion performance especially if you need to go below a 180 Main Air Corrector Jet, Then Mixture quality is rubbish and even if the Dyno readout says the Mixture is OK the power drops off, For that reason they really need Big Air correctors for the main circuit or better Emulsion Tubes (Needle Jets) with some bloody air bleed holes as FCR's don't have any at all stock.

Carburetors are not quite as simple as some people think.