I like to get out on the water early, and like nothing better than to be running out in the dark and have to charge up the glow spoon and flasher with the camera flash before I put it in the water. That said, if you really want to catch coho fish on the tide. Where I fish on the coast the hour before high tide and right through until the tide changes enough to start pushing you the other way is the hot time. Low slack can work too, but usually the water is so turbid from the silty tide flats that visibility is bad and the fish won't see your gear. So I pretty much fish the high - if the fish are around at all an hour or so is more than sufficient to fill the punch card for the day