I placed 4 horizontal rows (6 LED's per row) in the board.
Put another board on top of the components and rubber banded them together to keep all the components seated.
Flipped the board over and using bare 22 ga solid copper wire, laid a conductor down each row, wrapping the legs of the components as I went.
Then touched each leg with solder.
Then clipped out some sections of conductor to leave an in/out path along each row of 6 LEDs. (now 6 LEDs wired in series)
Top row, just the component legs sticking through.
Second row, wire laid and wrapped.
Third & fourth rows, soldered and clipped. (and another rubber band)
I laid another set of conductors vertically down each end so all 4 horizontal rows are now wired in parallel to each other.
This is the panel set into the tail light housing turn signal section.
Powered at 12.7v (2.1v drop across each LED). In the photo the light looks red but in real life these LEDs are yellow. (camera effecting the color)
First layer of diffuser added. (This one is a bit chipped/cracked/melted from multiple tests and fittings)
Second layer of diffuser added. (also a bit abused, but I'm just testing for effect right now)
Tail light cover fitted. (you can see the magnifying lamp in the reflection )
End results... It's not bright enough. You can still see brighter and darker spots where the LEDs are and aren't. Next I'm going to double up the bulbs and see how that goes.