JK, I hope I'm not trying your patience, but I'm excited to pass on a few of my ideas.
I spec'd a couple of knives I have that are similar in design, but not quite what I'm looking for: A Bark River small game based on the old Shrade Sharpfinger, a Frost by Mora, and a Koyote EDC.
3/32" (0.094") seems to be the way to go. The Bark River is 1/8", but is ground quite thin.
The Koyote knife is pretty close to what I'd like in a B&T: 3/32" carbon steel, long clip, 3.25" blade, 7.25" OAL. In handling this knife (very nice knife for an EDC or whittling knife), yet, I find it is smaller than I'd like for field work--especially if I'm wearing gloves. The Mora is a wee bit long in the blade at just under 4", but might be better in terms of OAL: 8.25". The Mora is a really good design, but I'd like a higher grind/less obtuse primary cutting edge and slightly longer handle. A 3.5-3.75" blade might be better, too. I'm not sure I've ever carried the BRK in the field--when I pick it up, it always feels too small and I choose something else (A 1st World problem, to be sure).
The general purpose handles of the Bark River and the Mora allow for some different grips. The bird's beak at the butt of the Koyote is nice, but can jab into one's hand; it doesn't really offer any advantages. All these knives have Handles that are too small for my XL hands. The handles get lost somewhere in my palm. Sure, quail and trout are small, but my hands stay XL -sized whether Im going for Elk or Cutthroat. ('Cutthroat' would be an interesting name for a B&T).
The Mora handle is probably the most versatile. Part of the reason for that is that the scales on the Koyote and the BRK are thick where the meet the ricasso, this makes it harder to pinch the blade near the ricasso. I find a pinch grip to be useful when filleting small fish (hey, I catch big ones, too!). The Mora handle narrows nicely at the ricasso.
The other consideration here is that if you are carrying this on a bird hunt or fishing trip, it is likely to become your default emergency survival knife. So a slightly bigger knife may offer a little more general flexibility. Thanks for reading my ramblings. I'm looking forward to seeing your design!