Welcome aboard mate.
What little I know about white fish.
I have caught white fish on dry flies and on nymphs.
White fish are hard to hook on dries but it can be done.
High sticking nymphs works much better.
Look for side channels with little pools of quiet water, fish the seam over and over, 10 or 12 casts, no fish, move on.
Be very, very quiet when wading, also when walking along the gravel, cover your wading stick tip with duct tape so as to not have metal on rock noise, spooks the fish every time. Or use a wood stick.
When it come to nymphs I have used small, #14 or smaller bead head, pheasant tail, or hares ear. Later in winter when the days start getting longer and it warms up a bit there will be midge hatches and small white midge fly will work. You can find these white fish flies in the sporting goods stores that time of year.
If your nymph fly is not rolling across the rocks and getting hung up once in awhile you aren't doing it right, also remember a drag free drift.
I hope this helps you out. Stay safe, getting wet in winter is killer.