Thanks to all for posting your images. I had forgotten I started this post quite a while back. I've since been able to get examples of each of the 6 WWII Canada Food Ration Books, and have made a listing. The coupons for books 1, 5 and 6 are easily distinguished because the patterns are different. The whole pane for coupons from Book 1 is the image of a flower, so each coupon has a different background pattern on the front, and text on the back. For books 2, 3 and 4, the pattern is the same, so they can only be distinguished by the number on the coupon.
Here's the list. The numbers correspond to the book, and each pane of coupons in the book gets a letter.
Book 1 (Aug 1942): a) sugar (red, #1-13); b) spare A (green, for tea/coffee, #1-13); c) spare B (blue, #1-13); d) spare C (brown, #1-13); e) spare C (brown, #14-26); f) spare D (grey, #1-13); g) spare D (grey, #14-26). 28 x 21 mm.


Book 2 (Feb 1943): a) tea/coffee (green, #1-13); b) sugar (red); c) butter (purple); d) butter (purple); e) spare A (brown, #1-7); f) spare A (brown, #7-13); g) spare A (brown, #14-20); h) spare A (brown, #20-26); i) spare B (blue, #1-13); j) spare C (black, #1-13); k) spare C (black, #14-26). 28 x 23 mm.

Book 3 (Aug 1943): a) tea/coffee (green, #14-29); b) sugar (red, #14-29); c) butter (purple, #27-42); d) butter (purple, #43-57); e) meat (brown, #27-34); f) meat (brown, #35-42); g) meat (brown, #43-46); h) C (black, half size, #27-58); i) C (black, half size, #59-90); j) D (orange, #1-16); k) E (yellow, #1-16); l) F (blue, #1-16). 26 x 21 mm.

Book 4 (Apr 1944): a) T (green, #30-45); b) sugar (red); c) preserves/conserves (orange, #17-32); d) butter (purple, #58-73); e) butter (purple, #74-89); f) meat (brown, #47-54); g) meat (brown, #55-62); h) meat (brown, #63-70); i) meat (brown, #71-78); j) H (black, #1-16); k) ? (blue). 26 x 21 mm.

Book 5 (Oct 1944): a) sugar? (red); b) preserves? (orange); c) butter (purple); d) butter (purple); e) M (brown); f) M (brown, #26-50); g) P (yellow); h) Q (black, #1-25); i) R (blue, #1-25); j) R (blue, #26-50); k) ? (green). 21 x 17 mm.

Book 6 (Sep 1946): a) B (blue, #26-50); b) M (brown, #51-75); c) S (green, #26-50); d) B (blue, #51-75); e) M (brown, #76-100); f) S (green, #51-75); g) Y (purple, #1-25); h) V (black, #1-25); i) X (red, #1-25);. 21 x 17 mm.

Pepere_Jack your butter coupon is from book 4, and your sugar coupon is most likely also from book 4, although I can't rule out that it is from book 2.
There are still some gaps in the listing, and numbers missing for some of the panes, so if anyone has additional images or just information, please share so the listing can be as complete as possible.
Thanks!