I'm also an NW45er my lipstick my collection consists of Girl about town, Chatterbox, lustering, &fun'n sexy,flash and dash, & impassioned for bright pink/corals and they all look good on me. I think we can wear almost any color with the right lip pencil and lipglass/lustre glass.
As far as the N collection i second 4n and also think 5N and 3n or 1n. I've paired the lighter colors 3N and 1N l/g with underplay l/s and chestnut l/p and it looks fab