If you are going to Hoodsport the hardware store near the hatchery sells a green fly that works pretty well. Otherwise I would go with a green cheater, just green yarn (small amount) and just drift through the schools.

If you are going out on the Sound then I would check out Salmon University's web site,
salmonuniversity.com. They have some techniques posted there for Chum on the salt.

In the river I use a purple and black maribou jig. Using that jig is the most successful tefchnique I have found to consistently hook chums in the mouth while on the river. I don't know why it wouldn't work under a float out at Hoodsport. Although I have not fished there for a while, I bet it would work if you let it drift through the schools.

Good luck!