ArtFunk, I have to say I am absolutely blown away by the quality of your work. Your Daft Punk and Tron helmets are the highlight of my visits to the RPF and I usually take a look at this thread at least once whenever I visit.
I noticed that you were having a smidgen of difficulty getting your light windows (for the lighted parts on the helmet) to have the appearance of being black, while also being transparent enough to allow for a good transmission of the light from (presumably) the LEDs you are using. I have seen several folks recommending tinting the plastic you use to make the windows, and while that can be quite good, and would undoubtedly make for a decent window for said project, getting the tint just right would be tough, and you would undoubtedly also have to go through multiple attempts to get it just right. I have a recommendation that would keep things somewhat economical and would be able to be reproduced time and time again much easier than getting the tint levels just right.
VHT Nightshades. Yes, the taillight tinting spray that some have used to blackout a visor (and I would also recommend for your visor as well) could be used to tint the little doodads (yes, I am from the south, and yes, doodad is a technical term). Here are the steps I thought of.
1. Create a positive mold of the hole you are wanting to fill in. Then use that to make a negative mold from which you could vacuform from.
2. Vacuform a small piece for that lens out of your preferred transparent/translucent plastic, trimming the excess away so that it fits flush with the outside of the helmet, while maintaining a good fit on the inside.
3. Using the VHT Nightshades, spray one coat of the tinting spray, let it dry, then follow the sanding/varnishing cycle at least 3 times to match the sheen on your helmet.
Voila! Your lens should be nice and dark enough that one couldn't see through from the outside unless there is something shiny coming from underneath (i.e. a lit LED). And then all you would have to do is mount your LEDs on a backing of some sort and glue it to your new lens and then that whole assembly to the hole in the helmet. Just need to make sure your wiring is free enough to route to the appropriate power pack and you should be set.
Hope it all helps, and I hope to be able to do a similar posting for my upcoming helmet/suit build. Peace, love, and beers to you all!!!!!