In the Fly Tying Listing there a Fly Terms from Perrault’s Standard Dictionary of Fishing Flies by Keith E. Perrault
Under “S”, you find the word “Shoulder” and it says…
Shoulder: The area just behind the head of a fly. Also, two short matched feathers applied in this area are referred to as shoulders.
Quality fly Normand! I would only suggest one more interpretation. On the dry fly I would look at the modern proportions as 60% body and the remaining 40% shoulder and eye. I would wrap the ostrich herl from the end of the body to the beginning of the eye and do the same with the grizzly hackle. ie. the grizzly hackle wound through the ostrich.
From the looks of your fly you separated the ostrich from the shoulder hackle (which is ok, your guess.) But is it the original recipe?. I have know idea.
Anyway, there’s probly a dead guy who can put this question to rest. Good luck.
OK…no red hackle fibers, so I sub’d red-dyed tippet. No black ostrich, so I sub’d dark dun ostrich. No Silver Badger hackle, so I sub’d a Ginger/Dun whiting that has some badger-like center markings:^)
Couldn’t wait to finish work so I could throw one together. LOL