Before closing the rudder I had to run wires for the tail light.
I remembered that I had a rudder bottom fairing from a damaged rudder that I had rebuilt for my RV 4, and when I tried the fairing for a fit on the bottom rib of this rudder... Bingo ! with a minor bit of trimming, a perfect fit and solved the tail light fairing and mount problem that has been overlooked by Class Inc.
For Anybody wanting to comply with normal aircraft lighting arrangements, a tail light is pretty standard stuff as far as I am aware, and a Vans RV 4 rudder bottom fairing is highly recommended.
Tail light and wires
Bottom fairing to rudder & tail light
Re-inforcing gusset plates around the tail light in rudder skin