Visor mandible width

well, I've actually sat down and messed with my DP95 that I stripped last year. I drilled a whole in the upper center ridge in order to center the visor. I've also cut a brass ring in halfe to glue into the back to give it the proper flair. The question I have is, how far apart should the 'mandibles' of the helmet be? The bottom of the T, the part by your jaw.:fettrotj

The bottom should be the same as the top. Pull the top in/out to match the helmets brow line at the top, then whatever distance that is to match the bottom, if that makes sense. The whole visor area should be flush so the visor fits right.

OK I thought it got wider towards the bottom.