Bless you Chickenman:drink:
Being an engr. when I first read the rant I was kinda thinking - so what - I work on some really old stuff and also have to meter stuff out but...
I have an early serial number 4610 and my $80 manual wiring diagrams (checked today) are not 100% accurate.

Here is my cunning plan...
My local JD dealer has an open door policy and have used it to corner Charlie the local service guru a time or two.
If I need some help with wiring or test point voltages etc.. I'll corner him and hope with my serial number, some tenacity and the JD service computer mother-ship I'll get what I need.
Something about going to the dealer and getting free coffee and Charlies time is rewarding to me.
Hope that the controller and some seat time make you fell better!