lighting and painting on clear surfaces can be hideous sometimes... when you illuminate, the transparency of the paint, or the variations in paint thickness become visible.  Depending on the thickness of the lines, you could buy a striping brush for about $10... although I once spent $45 on a dagger striper!  Maybe a crackle effect is more what your after?
_________________________
>Mac mini PPC / 1.42 Ghz / 1GB RAM / 74.41GB 4200rpm 2.5" / Airport + Bluetooth / 10.4.7 / 20.1" LG widescreen
>G4 400 PPC / 20 gig / 768MB RAM / ZIP drive / 10.4.7 /17" apple SD / Back up system
>Powerbook Titanium 1Ghz / 40GB / 512MB RAM / mashed up and waiting for a good mod!
>Macintosh SE/30