Since nobody is responding, I'll throw in my 2 cents.
The transmission is initially filled with Type "00" transmission grease. Then if it needs to be topped-off you use 50wt motor oil.
The engine can use 20w-50 motor oil. I think the originial specifications called for different oil in summer and winter back then, and would depend on the temperature conditions for straight weight oils.
The primary can use 30wt motor oil.
The engine fill level is shown on the dipstick.
The primary and transmission are filled until they just barely start to run out of the level-setting holes on the sides.
Can't help on the rectifier wiring.