I have seen this thread a few times, but been too lazy to post in it. I think you forgot a few important steps when you tinted your lights and the result, imo, looks like shit. I personally think that you should have sanded down the lights until they were dull before you tinted them, then I think you should have tinted them and followed that up with a finer sanding to make them smooth. After that is all done you should have used a machine polisher with some polishing compound to take out the rest of the imperfections caused by the sanding. Taking these extra steps would have produced tinted lights that were shinier and more 'finished'...not to mention the longevity issue of just spraying on top of a smooth surface.
Here is a link that will show a better walkthrough for tinting lights:
How to Smoke Taillights - Nissan 350Z & 370Z Wiki
If that is not enough, search around other car enthusiasts' sites and see what/how other people are doing it. IMO, I think your lights look like a half-assed afterthought, and could have turned out much better if you would have taken the time and effort to do it properly. Don't take it personal, this is just my $.02
more specifically search around my350z for taillight tinting by a guy named bubble...his turned out really good and there is a how-to in there somewhere