You don't really mention the end result of what you want to do, so suggestions are limited. You might want to look into using a simple servo tester like below (note that some servo testers only move the servo +-45 deg). Also standard servos have an ~5us deadband built in to reduce hunting and when straining under load the servo may be at a position slightly different than what is commanded. I tested a standard servo and was able to get ~425 discrete movements in its ~190 deg rotation range. Also, there is usually a bit of mechanical slop and flex in the inexpensive servo when operated under load.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14774