Grind the flapper off. New boats don't have them.

Eventually, you'll need to get a new halyard hook. The old ones weren't thick enough to deal with a 6:1 downhaul. The hook will eventually bend and shear off.

The halyard runs up inside the mast track, through the sheave (inside to outside) to the ring. The bottom exits through the center sheave in the mast base.

You can see how it's supposed to be in the photo:

You can also see how heavy the newer halyard hooks are.

17's like a fair amount of rake. You should be almost able to two-block the main. If you can, then rake forward a bit more.