I tie mine as WilliamJ has said, and counter wrap the wire forward. IMO, it's what you're used to doing that makes them durable, and I have seen them tied with the other methods & that does seem to work for some folks. If you get sloppy when tying with any method, the fly won't be as durable.
So, the best way to tie them is to be sure your using sufficient tension on your thread, hackle or wire & don't get sloppy with it no matter which method you choose.
As far as the hackle used, that can depend on what sizes you want to tie. I have on hand & use the bugger packs, strung saddle, saddles of various grades, and have used schlappen. I've sometimes used strung neck hackle too depending on the hackle I've gotten.
Schlappen is OK, but IMO is best for larger sizes, like size 2 & larger. The fibers are quite soft as flytire said. Schlappen is no different than any other type hackle, you still have to pick & choose each feather to best fit the hook size & it ranges widely in shape & fiber length.
When I use schlappen for buggers it's usually on really big sizes tied for bass, like 1/0 or 2/0.
I like that book as well & even have a few flies listed in it!