Hi Andy,
Wick is an easy slip to use and has a nice steep ramp into the river. Usable at most states of tide....... except LW Springs ; this is due to the big step at the end of the ramp....... beware of this when reversing down if you're there on the bottom half of the tide.
Shallowest water is in the middle of the harbour [ note there that the colour of the water changes from river to sea] ; at least the bottom is soft\silty.
The Run seems to have more water this year but is shallow near the outer red\green buoys.... getting out here is Ok up 90 mins before LW [if you trim up and drift out with tide; coming in, I wouldn't leave it later than 2 hrs before LW, but you can sneak in with the tide earlier [see above].
One bonus with using Wick is that the river water gives you an engine flush !..but for me, it is a long drag up\down the river at 4 kts. ....so I use Mudeford and am afloat and out in 20 mins!
Alun.