Internal Screw Post / Threaded Screw Post Stud Removal

Been doing a lot of research on the best way to remove the cross headed screw post stud on the inside of the 4th & 5th gen iPhones (iphone 4 and 4S) and I have found nothing in terms of tools that are made for these screw studs. The screws I am talking about are the ones located in the top right near the headphone jack (on GSM iphone 4) and under the battery connector (CDMA 4 and 4S). I have made my own tool by taking a Phillips #0 screwdriver and filing the head flat, then making the wings of the head thinner with a file as well. It works okay. I assume most repair techs use a flathead screwdriver. (I highly don't recommend them as they slip off the screw post while removing! this can cause damage to internal IC's and SMC's). THEREFORE, I NEED A SOLUTION IF ANYONE HAS ONE, ON MAKING A BETTER TOOL OR BUYING SOMETHING ALREADY MADE. I have not been able to find anything yet but I know there is a better solution than filing down a phillips #0 screwdriver for removing the screw post/studs.