Iain's sail is an Arne type, as is the sail I have on Arion. I can confirm that pulling back the throat hauling parrel on this type of sail does remove all the creases. On Arion I also have Hong Kong Parrels and Paul Fay style fixed luff parrels on the lower three battens. I don't need the HK parrels to control the set of the sail, but find them useful to stabilize the sail when hoisting and lowering in a seaway. I find, when there is a swell running, that there is too much surging otherwise in the lower, parallel panels of my Hasler/McLeod/Arne type of cambered sail, with its long spaces between battens at the luff. Fanned sails have narrower spaces between battens at the luff, and perhaps have different handling characteristics (as well as patterns of creasing). The Paul Fay parrels are used to induce automatic positive stagger to my parallel battens, which was a problem initially, but they also absorb most of the forward thrust on the battens underway. The happy result of this belt and braces approach is that none of my parrels (or any other parts of the rig) seem to be heavily loaded, including the HK parrels. Arion's sail has become a set and forget sail. It does have a bit more friction than a sail with just a throat hauling parrel would have, but I am happy to pay that price.