How do I remove stripped screws?

[Super]

I am hesitant to recommend a Rotary Tool for someone who is not familiar with using the tool especially in a small space. It would be very easy to ruin what you are working on and worse seriously hurting yourself. What I would recommend and is much cheaper is to forget about this shell and just find yourself another, possibly not running, engine and hope the experienced you have gained trying to get the first screw out will make it easier to remove the second screw.. At any rate, fill us in on your progress and if you succeeded and let us know any method you were successful with. Good Luck 👍

EDIT: My advice on your question of using a drill...it would be near impossible to drill that screw where it is with a bit straight enough to remove the screw and the risk for injury is the same as above.