You could add a strip of reflector on the top of each rear foglight lens to help with keeping each rear light 'circle' the same size. Many modern cars seem to have reflectors mounted low down in the bumper these days.
2 ways into a Puma rear light, front or back...
Puma lights mist up at the best of times (even from the factory) and I've yet to see a Puma rear light that
hasn't misted up even worse having been split and resealed...electrics and water :-(
You might this stuff useful
http://www.captaintolley.com/" onclick="window.open(this.href);return false;
I've used it to invisibly seal up a tiny hairline crack in one of the clear covers on my rear lights and it has worked well in reducing the misting up. PS: and I haven't even split my lights as I changed two lenses from the back!
Also don't overtighten the 3 rear light mounting bolts, this will cause stress cracks on the clear cover. Mine are only a few turns more than hand tight!
I'm not trying to be discouraging BTW, been doing the Puma thing for 10 years now. I hope it goes well as it will be a popular mod if successful. Just bear in mind Puma rear lights mist up even as standard! :evil: