I'm not the best authority because I usually hate concealers and just wind up with samples and refuse to buy the full size. I will say that as far as I can recall, I was closer to NW15 in some of the other formulas. I have some pro-longwear concealer in NW15 that was a good match and not on the light side. I'd say these Mineralize ones may run a bit light so NW25 may be the way to go for you. NW20 was a 100% perfect for me and I wear 1.0 in Matchmaster and NC15 in the Mineralize SPF15 cream foundation (which are both great matches for me too, without needing extra correcting).
When in doubt, go to a store and try it on in person first! I wouldn't dare buy foundation, powder or concealer without doing this, personally.
Just as a side note, if I didn't mention it already, I definitely get better coverage and staying power when I use this concealer over P&P Vibrancy Eye. It has some slight settling if I don't (although very minimal compared to every other damn concealer). With PPVE, no settling at all and the light reflective particles in it add just the right amount of extra luminosity to give a super natural finish - doesn't even need foundation on the rest of the face that way - it just blends in perfectly into my bare skin, which is fantastic.