There are many facets to your question, and I'm going to address just one, and that is the time delay between the actual tidal currents and the published high and low tide times. For example, on Saturday the 4th, low tide is 7:57 am at the North Jetty station. However at that time the ebb current is still racing along at about 4.2 knots. The ebb current rapidly diminishes after that, but doesn't stop entirely until around 8:30.
So if you cross right at low tide, expecting slack water, you'll find a vigorous (but diminishing) ebb current.
Why the delay? Here are some of the reasons.
* The flywheel effect of all that water moving in the ebb current. It takes a while to reverse the momentum of billions of tons of moving water
* The massive fresh-water flow through the CR entrance creates a bias toward outbound current, independent of tidal effects
* The ebb current is nothing more than water flowing downhill. But the narrow CR entrance just isn't big enough to drain the massive estuary in real time. It sort of backs up, and takes a while to drain
Chartplotters often have tidal current information built in that can quantify the delay. The online tool I used in this case is deepzoom.com. Here is a Deepzoom screen shot showing the 4th at the CR. The yellow arrows show the current direction and speed in knots, which shows an ebb current of 4.7 knots at the location indicated by the arrow. At upper right is a tide chart. I've set the time right at low tide.
Here's another shot where I moved the time slider until the ebb current stopped. Note the time is about 8:30.
Tools like Deepzoom can give you some idea of the delay between published low tide and actual slack water. But there are lots of caveats.
* There are relatively few locations (yellow arrows) where tidal currents are shown. In this example, there are no yellow arrows out between or beyond the jetties. So what you actually see out there will be different
* I suspect that Deepzoom and others use some kind of average for river flows. If Bonneville opens the gates, or a big rain hits, I doubt that Deepzoom adjusts their predictions
* On the CR wind is a major factor, as is swell and swell period
In summary, tools like this can be a general guide, but are not definitive. The bottom line is the time of actual slack water often lags the time of low tide shown in the tide tables.