1) It is pretty snug, yes. But it's not CRAZY tight. Vision? There really isn't that much - AT ALL. Vision is VERY poor in a Cylon helmet. Original ones were taped shut, I don't know if they put on new tape each fitting or just slipped it on. You can fit it on as a single piece -just watch those ears
Measurements are around the site, and some pics in the gallery have rulers, etc. Run a few searches in the forum and you'll get some great info. Check the Gallery in the Centurion section
http://www.byyourcommand.net/cylongalle ... php?cat=72 for all the pics. Red Eye has them all setup in easy to find spots so you can go to exactly what you are looking for.
2) The holes are lovingly called "Salt and Pepper Shaker Holes." They were the quickest way to add vision for the actor but in my view they result in Centurions having this funny "down looking" posture. Like you are looking over a pair of glasses, etc. But that's just me
Other vision options for hero helmets were a very narrow slit above the scanner. Everyone is focused on the red eye - not the narrow opening. I think there is a good pic of a slit/and a remake of it in Skullbeast's build thread.
Great questions! Important things to ponder as you start your build. Keep us posted on how it goes.
