New spin on H20

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.

Yes - that is exactly how I would do it. I would probably add a couple of inches for insurance and pin the hoist block there.

on my mast (mystere 5.5) I use a 1mm (maybe 2) dyneema bale (that is secured through a small hole I drilled in my mast track on each side, and hang my hoist block on it. This way the block can rotate a little bit on the bale when the mast is turning.

It also give me the ability to move the block up or down an inch or so if I change out the spin to one that is slightly different in size