I just finished the ribbed reinforcement plates and forhead plate, here's some pictures of the lower side plate.

 These were probably vaccuformed from sheet plastic originally so I made them in a similar hollow back/inside to be easily contoured to the helmet.




I now have all the basic parts modeled, though minor adjustment of parts including scaling and placement on the helmet need to be adressed.

I made a diagram showing the project status.

Screws need to be fitted as well. I have models of standard dome head screws I got from GrabCad. You can see them on the ear piece vent plate.