Hi Ray,
Both the gray Wulff and grizzly Wulff patterns call for brown bucktail for both the tail and wings. I have tied plenty of the grey Wulffs and the brown bucktail fishes very well for tailing.
As mentioned above, it is a little bit slow to tie with, because it has to be stacked, and bucktail, as you probably know, does not like to be stacked. I have found that to speed up the tying a little, I stack and then trim off the butt end of the long fibers so that a short set of fibers results. I then restack and repeat the trimming of the butts. The shorter stack of fibers stacks much more quickly than the stack of long fibers. You have to be carefull in doing this, however, and only take off a bit at a time. You can get too agressive in the trimming, and trim a lot of shorter fibers too much, and end up with a lot of fibers that are too short to use.
I also do the same thing using hand stacking. I do this by grabbing a small bunch with the thumb and forefinger of the left hand and trimming free with sizzors. I then grab the butts with the thumb and forefinger of the right hand and examining the bunch, I then grab the longer fibers using the left hand, toward the tips of the fibers, and then loosen the grip of the butts a bit with the right hand and then pull the longer fibers free of the bunch using the left hand. I then match up the tips of both bunches, combine the two bunches, and then trim off the excess length from the butts.
I repeat this process a few times until I have a bunch that is both short and thick enough to stack using a stacker. The key is to trim away as much of the excess length of the longer fibers as quickly as is possible. Short bucktail is not super easy to stack, but it is much easier than stacking longer bucktail fibers.
Regards.
Ganfolf