Can someone provide a list of approved circle hooks, please? Also, is there a difference in approved based on either bent or inline eye? Lastly, it doesn't seem that there is a standard with sizing of the circle hook. Is there a standard and/or matrix showing the size difference between two manufacturers using the same "size" i.e. 4/0 vs 4/0?
Circle hooks are not really approved by any single organization. The IGFA reccommended to the IGFA their thoughts on what an approved circle hook should be. It is listed in a "sticky" at the top of this forum. It is up to the individual tournament to determine which circle hook would be allowed.