I know nothing of this, but , if I were to start looking, I'd go to Fetlife, type in Gas marks in the Groups section and I'm sure you'd find people who can help you.

A disclaimer: I don't like sending you to Fet, because.....well.....we prefer to keep people here, but if you had no other reaction to this post, then finding help there is better than going on without direction . A 'lesser of two evil' type deal! Perhaps, after you've learned, reply to your own thread here, and leave us all more informed too?