Does anyone have links for great helm plans or measurements? I'm not really looking for anything specific, I just need a general idea on the dimensions to get started. Also, I'm mainly interested in English helms first and then maybe French. I have found photos for the Pembridge helm and illustrations for another in the Westminster Psalter both of which I'm assuming are English(?). There's also one on a knight in the Thirteenth manuscript, "Christ leading the Crusaders" but I don't know the identity of the group. The helm is very similar to a helm in a German museum, but I suppose it could be a lost or captured helm from another nation. Any help appreciated.

Here are two from the Armour Archive:

http://www.armourarchive.org/patterns/greathelm_ab/

http://www.armourarchive.org/patterns/greathelm_sinric/

I had not even thought about what to wear under the helm, so that is definately a consideration. Thanks for the links and advice. What is your opinion on brass accents such as the brass occular seen on some reproduction helms? In some of the dark- age illustrations the helms have their occulars painted a yellowish color and I thought that was a good indication of brass being used, but I really haven't studied the subject a lot.

Have you seen this?