I have a 19/20 Brembo radial master cylinder lying unused in the garage and was considering putting it on my NC30, but slightly worried about how it would work with standard calipers?

Will it be fine but a bit firmer improved power etc, or will all feel and modulation go and brakes will be on or off?

Your brakes will not have the feel they used to have,in fact they will probably have no feel at all
But so long as you have it why not try it.