Personally I'm not a big fan as it's so muddy... my only current experience of launch sites is Felixstowe Ferry near the river mouth. There are toilets and a café plus limited car parking. Tide can run hard across the slip either out to sea across a sometimes dangerous bar... or up river at the other end of the tide.
I think the boat club might allow a launch from the opp bank at that location.
You can launch at Ramsholt but not sure if permission/payment needed.
Also can launch at Waldringfield but I think that is a sailing club slip and may need permission/payment.
Then there is the Woodbridge end which I only know as a visitor on foot to look round Andy Seedhouse boat sales.... that place is worth a look... really old fashioned with everything from a £50 dinghy that would barely float to some nice yachts.
No launch from the slipway next to the RNLI station. Then you can tie up at the pontoon while you get yourself sorted. The slip is pretty well all states of the tide and it and pontoon free. Cafe and toilets right by pontoon plus a chandlers if you needed anything. You are launching into a quiet area (re sea state) and can then venture out to the actual sea as much or as little as you wish until you are happy with your outfit.