Thanks for all the tank resources and design considerations. I'll get back on the CAD in a few days and make some updates.
It was nice today so I crawled under the van to clearance some gussets for the 6V battery to battery series jumper. There are some slightly shorter batteries with less capacity that would not require this.
Below. The jumper test fitted to get a location. The 4/0 cable is routed in
electrical insulating sleeving from MMC and wrapped with spit loom.
EDIT: this is not the final cable. It ended up needing to be quite a bit shorter for an almost straight run between the terminals.
Gusset before: (This is actually on the other side than for the tray above. The layout is symetrical about the van centerline.)
Gusset after. Will be putting some edge guard around the opening.
I should be able to lift the tray most of of the way up, make the connections and then bring the tray up the remaining distance and bolt it in place.
Sun was shining on the front of the van so decided to mod the horn. Bye Bye Beep Beep. I had a small
private junkyard of S-series Saturn cars some time ago. I've owned many and drive a
95 SW2 as a beater. Great little cars and I have a barn full of used parts. Probably 20 or more horns. Now the Sprinter sounds like a couple of Saturn drivers having a honk-off.
Wiring. I cut off the OEM plug and spliced in pigtails that I salvaged with the horns. Same style weather tight connectors.
Install. Lighter bar is the OEM bracket. Black bar is 3/4 x 1/8 X 5 with holes at the ends on 4 1/8" centers.
And while the grill was off; painted the emblems.