Will,
Your fly looks very good and if you hadn't mentioned it was your first dee, I would never have known. As Sean mentioned, I always tie the jungle cock in last, as do all the good tyers of dee flies I know.
There is nothing wrong with having the wings sit a bit curved, some feathers have more of a curve in them than others. If you ever get to see in person and not in a photograph some antique dee flies, or those tied by the modern masters such as Veverka or Lemire, you will notice that the wing curvature varies from fly to fly because of this variation in feathers.
By the way, if you would like to tie dees on the long, flat shanked hooks used in days gone by, any of the well made 6xl-8xl limerick bend streamer hooks used for tying classic feather wing streamers of the Carrie Stevens style in #1-#4 work well, especially if you cut the eye off making it a blind eye hook. And if you want an extra long dee hook, the Partridge Carrie Stevens hooks that are 10xl are perfect (provided you cut the eye off it).