Samson recommends for a boat about your size 3/8ths, New England
10 mm, XLS breaking is 4400 lbs, assume working 10%, so 400 lbs working load (assuming halyard diameter is being determined by strength needed and not what is comfortable to your hand).
That eye hook has no support on the opening side, this is a silly part to have here, at best the working load listed for them is half what you could be applying. It is no wonder it bent. (The snap shackle in your picture has no relationship to the link given, is the eye hook not in your picture?)
Making the rash assumption that line strength is proportional to cross sectional area, you need 9 passes of the leechline, or about 5 loops to have about the same strength as your halyard.