Surely it would also depend on how many turns of body hackle were made as well.
Locking in the palmered hackle is the point of the rib and if it's a "skinny" fly then there will be less rib used.
To be honest I can't recall Kingsmill Moore ever talking about the number of turns,or size of wire, just the rib being oval gold. And I agree that it should be oval (although it depends on what I have in my kit at the time!) in order to show through the claret dubbing and the double hackle.
Oh, and +1 on the Blue Jay. It might be a pita to tie in but nothing beats a BJ
Which brings us back to flies being built at a cost and being tied incorrectly. A good reason to tie your own but are we not seeing the old patterns becoming wrong and that "wrong" being the norm. I love a variation in flies, the new and improved Loch Ordie being a great example, but I do like to see "classics" tied properly. By properly, I mean the right ingredients and not how many turns of rib
I'm also not adverse to "inventing" a fly or two, but I taught myself to tie the classics properly before I got inventive.
Ben,
As for the black and claret together, it probably doesn't really matter. But hold one of each up to the light and I think that the double hackled one has a different "aura", if that's the right word, and bulges the water better.
Once again that could just be shite...