The ones from the second OP pic will be fine, but they will, of course, have to be drilled out to make them lighter, sent to a specialist for poweder coating and some custom stickers made up form them. Something like ‘One ####### valve’ or similar
What started out as a bit of a piss take has brought to my attention the idea of using Lego Stormtrooper heads. I shall start a new thread shortly if I can’t decide which.
[*]I will post pictures later. I have a Darth Vader head up front and a Stormtrooper out back however any helmet from a lego mini figure will take a car valve. I used loctite super glue but I’d say any strong glue will work. Loctite was the lightest ;-0