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.

Very hard to get a nice even effect if back spraying.. the translucent is much easier to do.
If you wanted to go with an all vinyl solution, the you only really need to make the blockout for the back using a plotter. I spray the mask as it gives a more authentic looking backglass.. normally i put a spray of clear over this also but didnt do that on the Zaccaria glass as so little is blocked out.
The bulbs shouldnt affect it... vinyl is 10 year full sun, so unless you are using much cheaper banner vinyl i dont see any issues arising