I'm pretty close on this, but I don't quite have the pic you need exactly.
I have seen that "under-the-seat" setup mentioned above, but I didn't want to have to extend wires.
I'm putting wiring (CPU, TAC module, Relay and fuse block) all above the passenger's feet. I'm not finished yet, so I may need circuits I don't have, and have to add some things.
Space above passenger feet.
You can see the piece of metal I cut to the same shape laying on the table there.
Closer to finished. A block with fuse spades goes there on bottom.
I plan to weld some bolts to the firewall to act as studs. Then cut some slots into this metal panel, so that it can slide on those studs, so that the whole panel can be removed with 4-6 nuts. It should make it much easier to work on that way.