Go ahead and ignore most of the arguing in this thread.
I have tried all of these methods in a lot of different scenarios. I work on motorcycles and small engines on the side.
Using the dermal to cut into the screw is not a bad idea, but I have a better one.
Using a impact wrench (electric or air) is also not a bad idea. The problem is this though:
Impact drivers are meant to implement a high amount of direct torque to free a bolt. Obviously no one is talking about using an air tool to do this, but think of it like that, 300-600lbs of torque on a screw head that will most likely snap off at about 30lbs of over tightening will probably break with the loctite, especially is applied quickly.
I am surprised I have not seen this suggested in this thread yet, ever heard of an EZ- out kit? Drill the screw out!
You do not need to use an expensive extractor, you can get these tools for five dollars at your hardware store. You only need two, a drill bit, and a square bit, The bit needs to be SLIGHLT smaller then the square bit.
You will use the bit to drill a hole straight into the screw, then hammer the square bit into the hole, creating a square hole out of the round one, and forcing the bit in place.
Leave the bit in, do not remove it. If you have an easy on/off attachment I would use that with the drill because now you have to get the drill onto the square bit which is still connected to the screw and board. Do not wiggle the bit or it will come free. Try to get the bit as deep as possible.
Put the drill in reverse and apply a tight tiger, do NOT use it like a torque wrench, you will strip the head again assuming it is an aluminum screw.
It should come free. If not, you can try a torque wrench at this point, and if that further strips it, a true east out drill extraction kit. (Reverse drill bit)
Here is a square drill bit, I would look for one with a bit more length on the actual bit.