Probably goes without saying but vaping the nicotine would be the 80/20 approach here (or perhaps just 100/20), and I'll second that oral administration is also good. Lozenges in particular seem to have no downsides as long as you can find a flavor you like. (gum is great but stains your teeth) (EDIT: the gum probably does not stain your teeth, or at least I can't dig up anyone claiming it does)