Around Colorado, many people refer to both as "Green Drakes". Even in flyshops, when staff says that drakes are hatching, and I ask if they are flavs or flavilineas, I often get a blank look. So now I just ask what size. Like Byron, I use the same patterns in different sizes for both.
To make ID's more complex, we have drunella coloradensis which is called small western green drake. They are the same size and color as flavs. Luckily, the trout don't seem to care, so I don't try to make the distinction. I just call the smaller ones flavs, and the larger drakes.
Oddly, sometimes a Royal Wulff will work better than more imitative patterns.
I'll try the Jacklin pattern this summer. I hadn't realized that he used hackle and hairwing until I saw Byron's photo.
Thanks