Rent, buy, or borrow a vacuum gauge (I got one cheap from Napa). Remove the vacuum hose from the port on the side of the intake manifold that runs to the vacuum wiper. Fit the hose from your vacuum gauge to that port(nipple, what ever). When you adjust the idle mixture screw and the curb idle screw, you want to adjust for the highest vacuum reading while maintaining a good (and smooth) engine idle speed.
