[Al Skierkiewicz]

Cronos,
As to heavy, medium and light duty switches, some manufacturers actually use the same internals for all of their designs while strapping a different handle for each different application. There is no difference between solder and screw other than the weight (screw adding more) when properly terminated. The solder gives an extra measure of reliability/comfort.
Something to remember is that all switches have switch bounce, a little noise right after the switch makes contact. Know that it occurs and have your programmers compensate so that a noisey switch doesn't get the robot into trouble.