Ken,
Keep it coming,the most interesting thread we've had ! One of the things about aircraft enginers/techs/mechs is that they are fixers with initiative,somtimes to our own detriment!
I did many years as a flying spanner and I used to carry my house on my back, in terms of tools.Carried a hacksaw+ spare blades and ,incidentally a hand drill - didn't always have access to pneumatic or electrical power for a drill (saved my bacon a few time!) and always carried a mulitimeter.
Suspension of disbelief is fine by me,plausability helps of course !
More power to you Ken,good luck,keep the questions coming and let us know when the book comes out !
Another thought,do pax life jackets still use salt water batteries ?
Also relatively easy to make salt water battery,plenty of electrolyte (salt water) and material to use as electrodes,you can get around low output by making a 'battery' of cells.