Maybe try using a file to make flat sides on the outside of the head so you can use a wrench on it? (Not sure if that would be better or worse than the Dremel/slot idea… you would risk scratching the surface of the object it’s on.)

I think I made an unclear comment, lol. I actually meant it in a good way. It looks like a strong knot that holds up until it’s time to take it apart, in which case it would be somewhar easier than a bowline.

The right one looks easier to undo than a bowline.

Here’s a story for you: Poisoned trees gave a wealthy couple in Maine a killer ocean view. Residents wonder, at what cost?

TL;DR: it’s not worth it.

for more anatomically-correct horses