Hi, GYB, the design is nearly there,
As mentioned, keep the wing as flexible as possible, I use woodduck fibers, about 12 - 15 fibers, so the wing does not obstruct hook-ups. Tails should be flexible, those on your fly aare fine.
The difference I put into my tying of the USD is that I use the thorax cover method of splitting the hackle; then when the fly is completed and the lacquer on the thorax cover (pheasant tail cover) is dried, run the haackle fibers over your fingernail to make them bend up toward the wing.
This way the hackle barbs do not penetrate the surface and the fly floats totally dry.
Do not clip out any fibers which stick out over the hook eye, these stop the fly from tipping onto its nose.
You have a good design there; keep the wing slim.
What hook is that on your fly?
Here is one of my EasyPeasy USD duns..
ok, make it two...