The Shrimp flys I tie are on a 11/0 Mustad EZ baiter long liners circle hook
I use a dab of glo in the dark flashabou, some crimped nylon fish hair (.0006 dia) and either dayglo pink or chartruce chenille, I use clear nailpolish as head cement since I get it for cheap at the doallar tree store.
Since you are fishing the bay and a lot shallower think weighted keel fly and take a good hard look at a fly pattern called "Nine Three" I's a nice sub for an anchovie. The Bonito and Baracuda in San Diego loved that pattern when I fly fished them there.
I was tipping my hooks with a small chunk of salmon skin for the scent.
Here are some good sites for halibut fishing info
http://baytubers.com/
Great pictures there too.
And
http://www.swimbait.com/techniques/index.html
The halibut up here really like swim baits btw in case the flys don't work.
Think dark purple,
