The helping hands turned out to be no help whatsoever.  Never mind.  The swell manual is finished (apart from the ribbon cable, of which more later), the contacts tested, and the pistons secured.  The soldering is bloody awful isn’t the best, but it does the job: all the pistons pull to GND when depressed.  I’ve learned several lessons during my painful attempts at soldering this manual, which I will apply to future efforts.  The two most important being: Solder isn’t expensive, so don’t scrimp; and, flux is your friend.  But first, more coffee.

Pictures are during and after.  Don’t look to closely at the soldering; I gave serious consideration to blurring it out, until I remembered that I was taking the pictures with a potato anyway.