Great work there Retropin!
I experimented with a method for a BG repair last year and it worked a treat. http://aussiepinball.com/index.php?topic=6842.msg91095#msg91095
I failed to do a double strike print which you did, this is a good tip to enhance the colours once the translucent backing is applied. In my case I used a white adhesive vinyl, and have been experimenting with a spray of white paint behind the printed clear vinyl artwork.
For the blockout areas I have thought of using a white vinyl with a black print as a backing behind the graphics, all translucent areas could then be plotter cut and light would pass through the printed vinyl in these cut outs.
Long term I'm not sure whether the heat from the BG bulbs would effect or melt the vinyl, so the best solution would be to use leds.