hmm... the idea of a hand metal file is interesting.. can I choose any metal file or a specific grit / surface? Might go this route...No worries, everyone starts out at some point. Got a buddy or neighbour that wrenches on stuff?
It'd take longer, but even if you had a decent file you could make the driver you need.
I stripped one side of the jet with a narrow screwdriver.... Hope the filed screwdriver will work...