Wild One-

I recently read a great article about chironomids and wonder if these are chironomids. I'm not familiar at all with chironomids. Is anyone out there familiar with these little flies/nymphs?
Yes, from your description of those which had emerged and were flying around, they would likely be Chironomids. Hope this is not being unnecessarily technical, but the immature lifestages of true flies (Dipterans) are larva and pupa, rather than nymph. The primary reason I mention this is that the Chironomid pupa is the probably the most successful lifestage to imitate. It looks like this: