Hi all,
yes my experience is that the tension I pull on the mainsheet is greater the bigger the head on the sail. However like everything to do with sails, it is not that simple, on my Irwin main my attempts to achieve the leech tension I was looking for where hampered by running out of luff round. Mainsheet tension was bending the mast to the point I was flattening sail before I could get the leech in the head to stand up.
Ashby main has more depth, so I am able to pull on more mainsheet tension before the main flattens to much, keeping the leech standing up longer. However as I have found it over powers earlier, because of greater luff round and bigger head. It is difficult to have everything working the way you want all at once, but the sail is awesomely fast in 5-8 kts. as Tim on Mossie with spin and Chris on the F18 Capricorn saw last weekend.
I am still tinkering with settings and since breaking top batten in capsize last weekend, I am going to try stiffer head batten to see if this keeps head flatter and helps depowering. I haven't added more mainsheet purchases yet,just keep grunting, I hate having to use more mainsheet length than neccesary.
Regards Gary.