Before continuing with the instrument panel, I added two more duct flanges to the engine baffles.
This one is for alternator cooling..

…and this one is for fuel pump vent.

I also drilled the passthrough for the prop governor cable.

Next step with the instrument panel was to drill the switch holes.

The cable at the top is the parking brake.

I decided to place the alternate air cable and the cabin heat cable on each side of the throttle quadrant.

Finally I riveted the mapbox to the instrument panel.

I then went and primed & painted the instrument panel together with the instrument panel support rib I prepared earlier.
With that done, I could rivet it to the subpanel.

I am quite happy about the result. The rib really supports the panel well in this spot.