1979mazdarx7

So i'm going to get some new rims from a friend who has alot of tires...so i was wondering how to measure the size of the lugnut, like how far apart they are
i'm not sure if i should measure from the center of the lug to the other center across from it, or to measure from the 2 lugs next to it and where to measure it to, also how muh bigger than 13 rims on a stock suspension without causing issues to the clearance for turning