Main Sail Batton Tension

Light winds ("crew sitting to leeward"):
I like to let a little tension off to keep the sail flat and reduce drag.
(maybe controversial some people would say go deeper for more power)

Medium wind ("crew semi trapezing" up to "twin flat wiring but mainsheet constantly tight")
Enough tension to pull the point of max. camber to about a third to half way back

Heavy Wind ("twinning and crew playing the main")
Let some tension off to help flatten the sail and depower.

I would go with Strawberry on this, in light airs you want a flatter sail to help the wind flow over it. It is amazing how surprised a lot of people look when I sail on by them in light airs with a flat sail while they are there with a big bag in theirs. This is despite a few training sessions where I have pointed this out to them!

All you really need to do is look at most tuning sheets and you will see that (aside from mast rake where is applied and jib cars) the mainsail settings are very similar to the heavy weather settings......

yes i tottaly agree with you redback.  our battens are fine alex.  it will just break if we start fidleing!!  look at what u did to my trapeze elastic!!

Here's another tip about the battens.  Its difficult to mark them so that you know what tension you have used in the past. Use tippex its the only thing I know which will leave a mark on black tape.

Most cat sailors will just set and leave most of the battens.  May play around with the top one on a Fat top" sail depending on wind speed.

To flatten the sail in the really light stuff, just  add a ;ittle more downhaul.