I had a friend in the 501st edit this for me to fit the helmet I have for my OC

https://www.thingiverse.com/thing:4056779 - This is the helmet I went with so it fits it perfectly

I scaled mine up to 105%, same scale as my helmet, so the leds i used were 3mm flashing red and the led cradles were 3mm too, I imagine you'd get away with the same for a 100% scale