The best duck quills you'll ever find are by natures spirit, and available to buy from hook and hackle
Goose quills are good too, but only if you're tying on hooks bigger than size 4.
My initial impression is you are using hooks which are too big. Try size 6 or 8. Quill winged wets can be tied down as small as size 16 (in my experience) and probably smaller.
Goose and duck quills will give you nice splayed wings on the flies if you tie them in with the matte side ( the top of the quill) facing out.
When you use goose shoulder, the matte side out gives wings that are flat.
Its entirely up to you how and what quills you use...
I've been tying winged wets for over a year now, not that i've tied many lately.
There is a thread in the fly tying forum here
that has many patterns and some tips for tying the flies. Have a read through it.