Project stalled :(
But that's ok, I've been falling behind in projects around the house.
I came up with a battery placement solution. The batts I selected, lead acids, are 7"x13" x 12" tall, and there's 14 of them. I've decided to put six under hood (bonnet, lol) along with disconnects, controller, and such. Under one seat will be the charger and the other seat will have inverter and small 12v battery.
The additional eight drive batteries, I want to mount them under the cab, four on each side, looking like saddle tanks. Just waiting to coordinate a call with the owner, who's in Europe, and my partner, to approve the changes.