Yeh the stripped screw heads suck bigtime!
Cheezy screws combined with super tight tolerances and the fact that button head and flat head screws have shallow hexed holes makes it easy to strip em out.
All you can do is pre thread the holes with a quality socket head cap screw, like a motor screw and some grease. I've found that actually tapping the hole takes out too much material and makes it easy to strip the threaded hole.
To remove a screw with a stripped head you really only have a few choices.
Best choice is to have a quality drill bit and an E Z Out. Done deal.
Another is to Dremel a slot if you have access to the screw and a Dremel.
Or drill the head off the screw and grab the stud, again, if you have access to the screw.