For the spin you need two rivets to fix a block way up the mast. You then need to drill two smalls holes in the sail track to make a loop at the spinnaker top. That's it. Nothing more is needed for a spinnaker on the mast itself right?

For the downhaul, it depends on your setup. I have a 5-1 downhaul with just one pivoting block riveted in the sailtrack at the bottom of the mast and two cheek blocks on the side. That's two rivets per side, plus two for the block: total 6.

I guess a dual exit 8-1 setup would end up with what, 4 rivets for each exit blocks? Total 8.

So 10 rivets tops. What are you using the other for?

Just curious.