66 dart LED prototype working for now

Another method you may consider to get the proper variance between dim and bright is to make the inner-most 12 led's (per your drawing(and keeping the "outer ring" for running) activate only in brake/signal mode. Eliminating these 12 will reduce your lumens (hopefully enough) to get you the variance you would be looking to acheive.

This may not work. Just a suggestion from someone who has ample time at the soldeing iron.