Hi,
Big question... The true color depend of the light, if the day is sunny or not... you can have big differences...
MRP seems to be good, and some modelers have a special "recipe" with humbrol or gunze.
No the nose cone of the B is bigger. The kinetic nose is for the B variant, based on Taïwan's aircraft...
For the D, same nose than N except pitot (missing) and strippes all around.
Rom.