Wade, I have fished the Cowlitz quite a lot from the bank near mission bar. I have had the chance to watch A LOT of people side drift. They generally use flourescent green line about 8lb. test for their mainline. The reason for the bright line is so that when multiple people are fishing from a boat, everyone can keep track of where their lines are so that they don't get tangle ups every three minutes. Leaders are usually tied from 6 or 8lb. maxima ultragreen in the winter, and 4 to 6lb. ultragreen in the low clear waters of summer.
Fairly large, brightly cured egg clusters are generally used because their bait is in the water for long periods of time, and after a few hundred yards of drifting, you still want to have some eggs left on the hook. An egg cluster bouncing along the rocks can be ruduced in size faster than you might think.

P.S. Keep your drag fairly loose because fishing with this method tends to leave very little slack in your line when the bite happens, and I have seen many people snap fish off on the strike because they were using light line and had their drag set too tight!