A trick I use with small soft hackles in the 20s, and I use them a lot, is not to use soft hackles. Just use Whiting dry fly saddle hackle, the hackle that comes in 100 packs, same size as the hook. It works as well, if not better, than hen hackle, and I've used both. Much easier to deal with too. Tie it in as you would a dry fly hackle and just wind a couple of turns.

Hans Weilenmann's method works very well too if you insist on a true soft hackle. Here's a link. I use this method for all my conventional soft hackles. You tie in by the stem, so breakage is less of an issue. http://www.danica.com/flytier/steps/.../buttercup.htm