This is the pattern directly from Zweihammer's CAD files, there have been some layout modifications to adapt to my cutting equipment (plasma instead of water-jet or laser depending on where he was outsourcing to).
Rivets are included.
12ga is available.
The four sizes offered are:
Small (for brows measuring 21 1/2" to 22 1/2")
Medium (for brows measuring 22 1/2" to 23 1/2")
Large (for brows measuring 23 1/2" to 24 1/2")
Extra Large (for brows measuring 24 1/2" to 25 1/2")
Helms are geared toward SCA requirements and allow room for at least minimum padding in these size ranges. With room at the top of the scale for 1/2"+ close cell, 3/4"+ at the middle and 1"+ at the bottom. This means that if your brow measurement falls to 23 1/2" you have a choice of a Medium with room for 1/2"+ or a Large with room for 1"+.
Small variables in front to back and side to side ratios can be affected in the forming of the kit.