Beef

Question: Dear Paul, Thank you for all your recipes on all the variety of items you have posted on here. I have a hopefully easy couple questions for you. When smoking packer trim brisket do you slice off all the fat or just some off the top layer? If you trim the fat rather than completely remove, how thick of layer is optimal to leave? I've done a lot of smoking using your methods with great results. This is something I've wanted to know due to more fat the more heat and marinade to use but it also keeps it moister when cooking. Thanks again!