You`d be better with a HW or a Twink .
There is no need to worry about procedure for an air rifle. Having very little knowledge of RF rifles , i cannot comment , but you obviously need to know if the air rifle is a 1/2 inch UNF thread or push on . If its a push on , then you could use an adapter ( if teh said moderator is threaded ) .
You could have a word with Davyt63 , Festa , or Marksman for a Twink , im sure they can help with those .
Buster.
Out of interest , which air rifle would it be for ?