if your cutting the upper arms yourself, the best angle is flat, by that I mean a straight line from the balljoint plate to the bushings works best on S-10s with large wheels.
thats the angle I use on my tubulars to lay 22s on S-10s.
also use the Autodrive K5208 aftermarket balljoints since they have several more degrees of travel than a stock or most afterkarket balljoints.