As far as trying on all the different combinations---I used to have an auto racing safety equipment business, and I have been racing for 18+ years owning 6 different helmets.

I found HJC SA rated non-Carbon fiber models here:

http://www.extremesupply.com/hjchelmets/hjchelmets.htm

I found HJC SA rated Carbon fiber models here:

http://www.thebellstore.com/Auto/HJCHelmet...utohelmets.html