How to tie a Roman Helmet?

[Gaius Colletti]

Hi, I have just recently gotten into the re-enactment hobby, and was able to get a hold of a helmet (some sort of the infamous trooper helmet). Though I was able to get it for $15 and figured it was a gateway into the hobby, and I plan on upgrading in the future to an actual replica helmet. However for now, I have this trooper helmet.

Because naturally this cheap helmet lacks anysort of loops tie string through, as a makeshift solutions, just to see how it would work, taped keyrings on either side of the cheek guards, but have recently seen strings which appear to to hang from the back of the helmet, and are pulled forward to tie around the cheekguards, will this make the helmet more stable?

My bigggest concern is that while I am moving my head around, that the helmet stays in place, which for the most part it does. However is it possible to keep the helmet stable while say looking at the ground. I use a cut up, and folded up shirt as arming cap, but is there anything else I can do to make the helmet more stable while I am moving around?

Please, I know the trooper helmet is much hated (and for good reason, I agree) but I am looking for real help, so please do not post "Throw it away" Thanks!