Curious that it has horns as 2 reefing lines showing in pictures so assume in boom reefing so why the horns? Just pull on red or blue line? Our attaches with a large shackle to the sail tack .
It looks like you have single line reefing so you don't need the horns at all. We have the same and have the horns removed and replaced with a single eye for attaching the tack.
I have a similar set up. The horns are there for the spectacles on the third reef. Reefs one and two use cars to hold down the luff But you need to hook on reef 3.
In my case the big hole shown on the drawing is used to secure a shackle which holds the main.
It ios very desirable if you an do it to get the tack close top the mast (ie against the pull of the outhaul) This will alleviate pull on the bottom slug or bolt rope and get the bottom corner of the sail really flat. ol'will