Hi Nordwest,
The batten tension does not really affect your camber rotation. So you can keep the tension as it should be.
Counting from the bottom batten;
#1 + #2 + #4 you tighten good, so that the battens have profile
#3 you tighten so there are no wrincles in the sail.
the rest of the battens up, you only tighten so that they are with tension. Important is that they do not have any profile. Meaning they do not twist from one side to the next.
Then you need to test your camber tension. This being a formula sail, it will have a lot of tension on the cambers as we need a stiff profile in the sail.
test the top 3 cambers first by putting both your thumbs on top of the mast and with your other 8 fingers you press the camber upwards (as seen in this video) click
The camber when you press them up should say click/click over the batten (not rotate), and then pop down again. If they are too loose they will feel soft and you will need to insert spacers. This should be done until you have the required pressure. (every time you insert a spacer rig the sail and fully downhaul and re-check)
Once you have the required pressure on all the top 3 cambers, try the sail on the water again.
The bottom camber is normally harder than the rest but will rotate once the other 3 are over.
Do remember this is a formula sail, you will need to pull the sail hard into the wind to make it rotate.
Less downhaul will only resulty in a not optimal performing sail and is also not a valid solution to get rotation.
Let me know if you can get it to work
Dennis /P7