Given the tidal range you're talking about, it would probably be wise to cross the stern lines. That will help keep the boat centered yet allow it to move up and down with the tides better. Using longer docklines, like leading the aft spring line to the aft cleat, rather than to a mid-ships cleat will help with the boat in coping with the tidal range.
IMHO, you should be tying the docklines a bit above center...not at the top or bottom of the range. If you tie to the top, you have to have more slack to make sure you can go all the way down.. if you tie at the bottom, you have to have more slack to make sure you can go all the way up... tying in the middle or just a bit above it will minimize the amount of slack you need to put in the lines.
You should also be using synthetic chafe protection sleeves. They're made by a bunch of different companies. Some are designed to slip over the end of the line and tie into place, others will open via a velcro flap and then can be put over the line and tied into place using a thin cord. The ones I have are by Taylor Made.
Rubber or plastic hose and leather wraps make lousy chafe guards since one thing they've found on nylon dock lines is that a majority of the failures aren't due to chafe, but due to the line failing from overheating due to internal friction, and leather, rubber or plastic chafe guards hasten this process by preventing water from getting to the rope and lubricating and cooling it. The synthetic chafe guards I mention allow the rope to get wet and cool down quite a bit better.
For a storm, it might also be wise to put out anchors fore and aft...to help keep the boat from moving in the case the docklines fail.
BTW, it was pretty obvious that the docks don't float, since two of the bolts holding it to the pilings are clearly visible in the second photo.
One other thing... don't attach lines like the white one going over the port toe rail to the cleats that way... cleats are strongest when the angle between the line and the axis of the cleat is almost parallel, and weakest when the lines are perpendicular to the cleat
. If that line were to become heavily loaded during a storm, it would probably have a good chance of ripping the cleat out of the deck—as it has far more leverage than the black dockline attached to that same cleat.