I only toe-in if the pads are short ones, or if the rim is beat. I'm of the opinion that toeing-in brake pads isn't really necessary on longer pads that are curved to match the rim contour. Many people make the mistake of too much toe, and it will wear unevenly and too quickly in my opinion. Just very shallow angle is all that's needed. Usually brake pads squealing is a combination of dirty rim braking surface and poorly-fitted pads. Old pads, which were rubber, tended to harden up and make noise. My quick fix was to always run some non-woven abrasive pad over the rim braking surface (or steel wool, from back in the day before scotchbrite was available), and to rub the pads on a piece of sandpaper held on a flat surface. This would true the pads quite nicely, and it would be enough to give the brakes some new life.