Here's the build process for a Hydra II, with pictures of the process.

This is the ITT inlet, as supplied by Modular EV power. You really only need a foot of cable, so tell them when you're ordering that you're building a Hydra and don't need a long pigtail.

With the outer jacket removed, the individual wires can be bent as needed in the enclosure. Note the resistor mounted on the inlet between 'blue' and the large green ground wire. That means that the blue wire is the proximity wire, and will be connected later to the "Inlet Proximity" terminal on the board.

The raw material from Polycase - the WX-42 panel, and the WC-40 NEMA-4 enclosure.

The chassis mounted components. The power distribution bus module, relays and board are, more or less, in approximately the positions they will be in when the assembly is completed. The power supply (lower right) will be under the logic board eventually.

The chassis has been marked for most of the holes. Not marked are the holes for the power supply and the ground bus. The power supply holes must be done particularly carefully as it's unforgiving. The bus bar's hole location is not nearly so critical as the rest.

The holes. The board gets 1/8" holes for 4-40 hardware, and the rest are 9/64" for #6 hardware.

The chassis-mounted hardware, bolted into place (except the ground bus).

The same, but with the logic board temporarily set on the standoffs. You can see the power supply mounted underneath.

the two holes for the cable glads, with one of the cable glads in place. The display will be on the left hand side of the chassis in this view. The mode button will be on the left side and the inlet on the right.

The panel temporarily set in the chassis. You can now see the importance of careful parts placement. There must be enough room on the right for the inlet and the very, very stiff inlet hot wires to be bent into place. There must be enough room at the top and bottom (in this view) for the outlet cables and cable glands to be installed without interfering with the chassis wiring.

A view from the opposite side, with the inlet holes now drilled. Notice that the inlet is positioned slightly too low. The #6 screws intended to hold the inlet in place will not be able to enter without hitting the panel. A dremel cut will need to be made in the panel to provide relief.

Same view, but with the logic board.

The inlet is now in place. You can see how loose the radius must be for turning the AWG 6 inlet hot lines.

The inlet wiring (more or less) fully installed.

The first car cable fully installed, as well as the power supply and inlet wiring. Note that there is no proximity line for these plugs, unfortunately.

Wiring is complete.