Yes the Serenity is a great board and maybe I can help a little.
Jibing the Serenity is very much an old school technique and is a little delicate as you have to react to what the board is telling you.
First a long smooth jibe. I place my front foot about 1 ft behind the mast on the windward side of the board and put as much pressure on it as possible, bring my front hand back to touch the harness lines and put the rig as far forward as possible. As the board starts to go away from the wind the back hand goes as far back as possible and the back foot as far back as I can and place the rig way over to windward, bringing the front foot parallel with your back foot. As the board goes through the wind change your feet and the sail and step forwards.
The board can be turned just with rig pressure but to speed it up a little you can put pressure on the opposite rail to where you are turning.
Now the delicate part, depending on the speed you are going will determine how the board will react. The Serenity is not a planing hull but if you are well powered up as you go away from the wind the board may try to plane. At this point if you are far enough back it will foot steer like a short board for a second but will change back as the board slows down. Tricky.
Once you have the technique there are no problems jibing the Serenity and it can do fast tight jibes.
I have found sailing down wind it is best to use the same technique they use in the Americas cup. Keep pressure in the sail and speed. So the stronger the wind the broader you can go but it is a very delicate angle. As if you go too broad you just stop and everything goes very unstable. I have also found it is best to try and keep the board in displacement mode and not let it try to plane down wind. So learning to feather the sail is important.
There is a link on the Free Forum on page 2 of a video of me sailing the Serenity which may help.