I'm very pale most of the time, with dark brown hair - NW15 is too dark, but I don't know what my actual colour is. I tried Max Factor's FaceFinity Compact Foundation in 01 Porcelain recently, and that seems a fairly good match.
Unfortunately I can't try any MAC in person as there is no store or counter near me, otherwise I'm sure I'd be in there regularly spending way too much money lol.
Maybe that's not a bad thing!
If you like the sound of a dense texture, along the lines of Toxic Tale, Runaway Red might be very nice on you - possibly will show a bit on the pink side, if your skin is very pink. It's a deep color, but it's not dark, since it's not blackened in any serious way - just a tiny touch so it's not neon bright. Layering more on makes it appear deeper, but one smooth layer is pretty much mid-tone and good for daytime for anything except maybe full summer sunshine (a lighter pencil or lipstick underneath or a lighter gloss on top would take care of that).
Most MAC reds are neutrally balanced between blue, brown and orange tones or are just on the warm side all the way, so Runaway Red is outside of the norm. The Satin texture might be too matte and dense for some tastes, but if you don't mind it, the color itself ought to work fine on you. If you don't own a lot of red lipsticks, because they never look right on you, this might actually work really well, but I think there's a good chance that we'll see another really good blue-red coming up with Eden Rouge mattene in Posh Paradise (that one will be lighter and brighter, but looks less blue).
NOTE: Did you like the red Dare to Wear lipglass - Bold & Brash? That's the last MAC blue-red lippie that really worked well on me, but Runaway Red is more stylish and a richer, more luxurious color overall than that one. I wanted to like Wicked Ways l/g, but it didn't do much for me and just looked ordinary - it was too balanced. I only do well with very obviously orange or blue-toned reds and prefer blue based, because they bring out the blue tones in my green eyes better. Strut Your Stuff from Peacocky really popped on me, but isn't a color I could just wear on its own without blush, since it made my skin look a touch sallow, since it's so orange. 'Just to give you more of an idea on Runaway Red - hope this helps.