I received my set of red LEDs today. I think I'm going to return these side-firing pair you show above - the same 6-element red 194 LEDs do a much better job at filling up the rear side marker lights. I'll wind up with 2 pair of these:
You are correct that the red LEDs behind a ruby lens makes for a much more saturated/vivid (and brighter) red light. My tail/stop lights look a bit pale in comparison. I guess I wait for a 4th of July sale and get the Triton lamps for stop/tail as well as the amber (no switchback needed).
I compared the wife's Camry Hybrid w/stock incandescent license plate bulbs side-by-side against the CX-5 with the LED 194-equivalent bulbs and the difference was striking.
So far I've converted all the interior bulbs, the backup, license plate, DRL and fog lights w/LEDs - all from VLED.