Putting together a impression for a Wireless Op/Air Gunner, on a 1944 Lanc crew (my uncle's role in WW2). Looking at all sorts of pics in a half dozen or so books in my RAF library, web sites, etc., I see all sorts of variations of sleeve insignia worn by OR WOps - some with sgt. chevrons on one sleeve only, some with both, with or without shoulder eagles, some with gilt KCs over the chevs, etc.
Are there any good rules of thumb? Was there a period when chaps stopped wearing chevs on both sleeves? Were the gilt KCs common? If so, where do you get a pair?