G3 by hand doesn't polish anything? So why are there are instructions on the container for doing just that? I do have a mop, but for such a small area it simply isn't necessary. Power tools are for speed, efficiency and effectiveness; I don't want to compound a whole car by hand again. I have used this procedure for on lots of lamps, and find that the results are good for several years. Which as far as Omegas are concerned is likely to be their lifetime.
Farecla themselves say the G3 Paste (and indeed their Advanced Liquid Compound) should be used with a mop. It's formulation is as such that it doesn't become properly abrasive until it reaches higher temperatures than possible by hand polishing.
UV degradation/protection. I think the biggest problem with Omega lamps is actually baked-on dirt - you can actually see where the beam pattern does this - which is why a big improvement is so easily achieved. A look at other lamps shows different symptoms; the more horizontal surfaces on Focus or Vectra(for example) lamps usually show lots of little cracks which are more likely to be caused by UV, and aren't repairable. Although improvements are achievable.
Interesting theory - But not plausible. Baked on dirt? Why would an Omega suffer more than a Focus or Vectra (for example)? Does the Omega have super hot headlamps? No. The clouding of the headlamps is caused by the degradation of the factory applied UV protection. That's fact, not opinion.
Lacquer. I've not found any need for it. Nor am I convinced that applying it to an already polished surface is a recipe for durability. Occasional application of a good quality polish works for me; I use the same stuff on the whole car.
If you apply the polish very frequently, I'm sure it will help - It helps to keep paint looking shiny, so why not plastic? It's more effective on paint though, paint is covered in lacquer - See where I'm going here?