Freestyle sail trim

That's a difficult question to answer because the sail you are talking about is very old and freestyle sails have moved on since then.

For a start it would be rare to see any freestyler on a 6m rig. The modern way to rig a freestyle sail is also to use little downhaul, with the sail set with a tight leech for better acceleration. We then use smaller sails than others would choose for blasting. This is the opposite from a slalom sailors approach - where some (wrongly) say 'you can never have too much downhaul'.

What I would suggest is you use the sail with different downhaul settings and see what feels right.
You could also post a photo, because most sails have a setting that looks about right.

Basher is correct.
Top freestyler's usually use .7 to 1.5 meter smaller sails than rec experts, tight leach but deep draft when filled.
Pumping is needed, but a light feel when going is needed.

Cheers guys.
I used it some time ago while learning so didn't care (or understood the need) to trim.
I remember using it on a 165L board and going pretty well.

Being over 100kg, I generally go to a 6m when the winds are over 25 knots.
With what you all said, a freestyle 6m may be a bit too powerful for that.

Waiting for some wind to try it again.
Will do what you suggested and not down haul it like a slalom sail.

Mark, I wouldn't know how to set up a wave sail.
I can imagine it should be set with not much down haul (?)