On my 68 Dart, the reverse light panel is thin and long but there is just 1 bulb on the inside corner. I'm thinking about mounting something like this in parallel across the entire lens....so the entire lens will light up.
https://www.ebay.com/itm/10x-White-5050-15SMD-Panel-Led-RV-Interior-Dome-Light-Bulb-1156-BA15S-Adapters/253410200337?epid=12014370668&hash=item3b006ccb11:g:9VYAAOSw42dZEC7Q

If they made something like this in amber and red, you could fill the entire lens with light. Those Year One LEDs look kind of lame IMO.

Not sure why that link isn't working...sorry.