I did the same with my P-51D build Andy, because the paint i used for the NMF was fragile and i did not want to mask over it!!!
I decided to do the same with Mr. Color as i had no experience with their usage. Finally they came out really robust. One more reason was the insignia painting (little experience here too, my second attemp!!!). If something would go wrong i would have to wipe out all the paint...on the other hand ia had only the primer to wipe!!!
John