Ok, thanks very much, I'll give it a go. Do you know of a reliable method for finding the starting length, I've got a piped 48 on another plane and everyone tells me to do different things, one told me it was too short, so I lengthened it, then another (semi-pro) told me to make it even shorter than it was before???!!!! I did find a formula on an Australian pattern site but that didn't seem to help.

Oh, the joys,
Thanks for the help.