Yet one more idea that might work is a trick I sometimes use on larger seized fasteners on cars. Using a very sharply pointed punch (like a sturdy nail which has been sharpened) and a small hammer, make an indentation in the screws head out close to the edge (hold the punch vertical for first few taps) then tilt the punch about 45 degrees and while keeping the point in the indentation tap in the correct direction to unscrew the fastener. Repeated impacts will unscrew the fastener.
Also might suggest applying the tiny ammount of super glue to the tool tip not the screw. If you accidently squeeze out too much the overflow can be cleaned off the tool and the glue reapplied much easier than it can be removed from the screw and the surrounding areas of the device. Alternately the surrounding areas can be masked from excess glue with a bit of transparent tape.