The chute is off a Nacra f-18. Pole is 11'4" to the tip of the end pole hoop.
As fat as luff tension, I was pulling it all the way p and then letting off about 6", This put a lot of curl in the luff so I let it off till the sail flattened out ( about 18" ) seemed to help some the next day, but the winds were lighter also.
I will set it as you describe next time I go out and will mark the sheet.