I have a few favorite local patterns that I tie with various amounts and
size of hackles. As well as standard ties, I often tie them with both
undersized and oversized hackles as well as overly dense and sparse.
Depending on the type and amount of hackle used, the same fly will
provide a different profile and attitude as well as behave differently
on the water.

Willi

I think this is true of almost all of us who tie... if you ask a
flyfisherman who is also a flytyer for a peek in his flybox, you'll
typically see patterns you NEVER see in books, and you'll see variations
on standard patterns using a bit of a different color, or more spare or
more dense hackles, depending on the water.

I fish primarily in the Sierras and mostly on tumble and plunge pool
streams where the water is pretty fast between the pockets. You need a
fly that can float a bit longer in this type of water when you're
fishing a dry, so you make accommodations in the patterns, like heavier
hackling, use of different body materials that are similar in color, and
sometimes tying smaller flies on larger hooks, a bit farther back on the
shank.

Larry