If the screws are as tiny as most in the equipment we use(#4 or smaller): none of the extractors mentioned will do you any good. A hole large and deep enough to insert the tip of the extractor is required, and you won't have the material to drill in a screw of that size. If the wallowed hole that you left in the head is deep enough: that Sears set MAY work, BUT you've got to press it into the screwhead pretty heavily for it to bite. The best bet is to drill the head off(as suggested), and hopefully leave enough of the screw to grip with a pointy nosed pair of pliers. When the head is off the screw, the threads should loosen up considerably. Buy a good quality drill bit(nothing from china/taiwan, as they don't seem to know how to sharpen things like bits, blades, etc), and drill at a very slow speed. If the screws are stainless steel(check w/a magnet): get a cobalt drill bit. As the heads are recessed: If you try the Dremel idea, chances are you'll end up cutting into the top plate too. That trick works great with larger, non-countersunk stuff.