For a Mudeford launch you probably want 0.75m of tide to go out against the flow.
Now..........here is the (multiple) BUT!
If there is high pressure this can effect it - not by much but it can depend whether you are going with or against the tide.
If the bar moves (from some heavy swell) there could be a requirement for more water in the run.
Depending what the tide is doing can dictate as to whether you can get out the run. If you are"going with the flow" then no problem, if you are against the flow on a big tide in either direction (Ebb worse obviously as the 2 rivers are emptying at the same time) you can struggle as you may have to lift your prop and then you can't get any\enough speed! (take my word for this!, a member has also smashed a gearbox trying the "I can plane through that" approach)
There is a cost to launch if the hut is open - usually 8am I believe. (I nearly had a heartattack when he arrive at 05:30 one morning, luckily he was going fishing before work!). There is no cost to retrieve, so feel free to come back in any time without cost.
The parking is expensive - I paid