There is a some information available regarding this on the web and Bill A. Forth coming book will in my opinion be regarded as the bible on the subject, maybe he will add more to my response later. But u can give you a brief out line in the interim.
This is a quick overview on Canadian flashes in general. Depending on what era of WWII you are going for Printed/canvas titles are always WWII era, starch/glue back are late war 1945 time frame, slip-ons are early war but worn mostly in Canada, mid war British made examples some times reffered to as Aldershot weave are my favorites (but more expensive) the Canadian made examples are a little harder to tell but the backing material usually tells the story. Stay away from shinny threat and black backing that covers the back.
From my experience a lot of the of the ones you see on EBay for example are post war.