I am getting ready to order me a EFK barrel for my FNX45. I do not know which way to go. I can order a .578 or a 16mm. I have Sig that I am getting a barrel for. I can only get it in .578. I am also planning on getting a threaded HK45. The HK comes with a 16mm. No matter what I do it looks like I have to buy 2 adapters for my can. What threads do you guys think are better and why?