I also stripped the head of the 3.9 mm screw but I had inadvertently used a JIS 00 bit rather than the Phillips 00. I had to cut a notch out of the corner of the bracket (which is made of aluminum) with a hacksaw blade so I could then cut a slot in the stripped screw head using a Dremel cutting wheel. This is unlikely to be a problem with any of the torx or Y, but do take extra care with all Phillips heads. If I did this again, I would compare the fits of a 00 and 000 Philips bit on the 3.9mm screw. Good luck. The rest of the disassemby / reassembly went smoothly thanks to this excellently documented guide and helpful comments. Thanks everybody!

I hae the sae laptop with ost of the lower lettered keys ot workig as you a see How did it go?