I'm helping a friend install a spin on a hobie 20. We're using a carbon windsurfer mast for the spin pole. The spin is more of a runner than reacher. My question is this: What's the best way to locate the attachment on the mast for the spin halyard block so that the spin luff has enough tension and room for adjustment when the spin pole is properly bent? Is it enough to measure the spin luff and use that to approximate the distance from the tack attachment on the pole to the spin halyard block? Thanks.