While I was waiting for the pic to load, I read the text and was wondering what the Poncho taillights would look like in the tailgate.
Wasn't too sure how it would work out, but now that I see them I really like it.

Having the license plate down under the bed looks good as well.

I'm a big fan of the 39 Ford taillights and have them on both roadsters.
The 32's lights are pretty bright compared to my friends old hot rod - a 1938 Morris w/SBC, sorta looks like an Anglia - who also ran 39 taillights.
Mine were made brighter by the chrome paint in the taillight bucket as well as the Bob Drake replacement Halogen bulbs for the original #1157 buckets.

His new car is a full fendered 29 Roadster, again with SBC - works for him, runs hard and strong, danged Chevys anyway - and now runs Pontiac tailights with #1157 bulbs.

A totally subjective comparison with the 39 taillights in my 32 - now equipped with #1157 bulbs cuz one of the Drakes burned out (after several years of regular use) - showed the Pontiac taillights to be brighter.
His Poncho taillight buckets are still black inside, but may get some white paint later.

I ordered up a pair of the Poncho taillights and may install them in the 32 solely for the mo-bettah brightness factor.

One of the guys on another board I frequent ran some sorta scientific tests with a sensitive light meter and a pair of Poncho taillights.
The baseline was original black painted buckets with #1157 bulbs for all tests.
"Chrome" rattlecan paint was about 20% brighter.
White rattlecan paint was 60% brighter.
That due to the titanium dioxide in the white paint which offers better reflectivity than does the Chrome paint.
And way more than the black paint.

Lotta guys pooh-pooh the brightness factor of taillights and just don't worry about it.
My question is, after all the hard work to build a nice little car why jeopardize it with small and dim taillights?

Third taillights are a viable option for most hot rods.
Trick is to have a traditional looking one.
Perhaps made easier in a roadster pickup by frenching one into the rear of the tub.
My thoughts for the 31 on this subject are to adapt a 37 Ford or 39 Chevy taillight to a level adapter mount and set the single taillight on the sill in front of the trunk lid just behind the cockpit's rear rail.
I have a billet one on the 32 and it does seem to help the idiots following to see the stoplights.