I recommend testing the electrical current before making a determination of length...

Something not mentioned here is hooking power of the rod when the "drop back" is too long. In most cases 10-15 feet is the furthest you'll want to run. The flasher will work correctly and hooking power is optimal. The further you "drop back," the less hooking power you'll have.

I hear a lot about water clarity, light intensity and so forth... Remember this, a fish is go to hit regardless- he's hungry or aggreviated! Take a look at coho. They'll hit right next to the boat!

Chinook are the same, however they do require so sense of protection (wind waves, ripple, low light periods, etc). Most of my Kings off the Puyallup this year were caught 20-25 feet down with a drop back of 15 feet!

Experiment a little and find what works best for you. I do recommend taking notes on the different lengths you decided. I am sure you'll notice a difference in the amount of fish that are in the boat when you shorten the length..