Thanks for your picture Mark. I am doing the same thing, minus the spin-lock. I do not like the Spin-lock brand cleat because if you accidently kneel on the line passing through it, it will lock. I had one on my Inter 20 and it ruined many a take-down. Then it broke and wouldn't hold the halyard up. I find a simple cam-cleet, like on your beam in that picture is much easier, and pretty fail-safe after you release it, it's not going to re-cleet itself as the spinlock will do.

Now, why are you using the spinlock at all, as you the way I see your rig, you are running the halyard down through that block on the beam, out to the tack line back to back block, then back through the cam-cleat? Or was that cam cleat left over from the old tack line setup? Or is for the jib car adjustment?