So, do you ever epoxy the wing case?
Nope..... never. Just a little head cement on the thread and if it gets a bit into the wingcase fibers at the tie in point that's fine.
They're durable little guys with the counter wrapped abdomen and then opposite wrapped wire, and quick to tie so if one dies an honorable death you don't mourn very long LOL.
Unless you get heavy handed with the hemostats they stay together pretty nicely.
The little detail trick in tying the wingcase is that the abdomen is one small 3 strand twisted bundle of tail fibers wrapped and tied off ....and then wingcase is a separate tie in of 5-6 tail fibers making sure that a solid black barred section is going to be the wingcase. The dark wingcase is important so I don't just randomly tie in tail fibers at any point...always so when you flip that wingcase over flat and anchor it ,it's a solid patch of dark fibers.
You could even use goose quill at this point but I like keeping it basically all pheasant tail and that black barring makes for a darker more pronounced wingcase.