Hook vs cord #breaktest

We keep including some cord with hooks when people order them but I didn’t know if 4mm was strong enough so here ya go! Breaking my own gear fear 😂. Tying a loop with a double fisherman knot makes it too long when inches matter while aid climbing. A flat overhand is my favorite way of doing this? What’s yours? I’m open to ideas on how to do this better, I just don’t want to send people gear they can’t use without doing something to it.