Hi Vikingsail, I've heard diverse opinions about sail battens. I used to tighten them a lot to remove all wrinkles. My shophandler advised once to keep them rather slightly loose, even on high end sails. This would ease rotation and only marginally affect performance (I haven't tried yet).
Hi Kiwiben, I guess you spotted the first two most common mistakes, the third may be incompatible mast/sail. You still see summer sailors with mast too long/stiff and 10" clearance between sail and board. Board too big? Hmm... given your 100 Kg it must be huge.