I don't think there's any real fuss among all of those persons truly knowledgeable and electrical engineers and electrical techs and John Deere mechanics about the system, the John Deere Service Bulletin 268,,,,,,,,,,,, and allllllllll John Deere Wiring Diagrams,,,,,,,,,,,,, and alllllllllll John Deere Tractors,,,,,,,,,, show/have the 2 wire 24 volt devices (Starter, Generator) as FLOATING and insulated and electrically isolated from frame chassis ground and certainly NOT POSITIVE GROUND as has been erroneously posted here (perhaps that's the fuss you're thinking of???).
The center series tie point of the batteries (+ of one, - of other) does have an attachment to frame ground, that way there's two 12 volt (with respect to frame chassis ground) A & B circuits up to the switch as the diagrams show. In addition to the 2 wire FLOATING NON GROUNDED 24 VOLT SYSTEM there are 12 volt devices like lights etc.
Piece of cake, and no fuss as far as myself and other electrical engineers and techs and John Deere mechanics are concerned.
You new here? I dont recall you before and I been here over 15 years, but I dont remember every poster lol. Regardless Welcome, best wishes and God Bless
John T Retired Electrical Engineer