Doug, if you have a copy of the book in question, it might be more helpful to the original poster to supply some detail from your copy, since the book is long out of print.
I have a copy of the book from the university library and am hard pressed to find answers "everything" the original poster wanted to know.
If you had a detailed reply, I'm sure it would be appreciated.
I used to have some information on regimental insignia on the main website but am still working on recreating these information pages.
What I can tell the original poster is that The Royal Montreal Regiment mobilized an overseas unit that evolved greatly over the course of the war; it is mostly remembered for providing the headquarters defence unit for 1st Canadian Army. As such, it wore the formation patch of that formation - i.e. the red diamond with blue horizontal bar down the centre. The shoulder flash was in khaki with buff letters. A helmet flash in regimental colours can be seen in contemporary photos also.