There is torque specs for the toilet paper holder at GM,my point is theres torque specs for every bolt on everyting,take some time and google torque spec for duramax valve cover and so on and so on write it all down so have that info in hand.Pick up a tube of grey sealant.Pick up all new seals and o rings lb7s are hard enough as it is to have to redo something that is leaking by could be a ton of rework.I personally would pull every injector cup and reseal with red loctite ( the tip of the injector cup has to have red loctite back on it i put it on the 45% and all around the outside all the way down) as soon as you get it back in the hole install the injector and torque it.some of the injector cups may be coated on the inside with carbon and stuck to the injector when you pull it,if you damage the cup trying to get it off the injector throw it away and get another dont take a chance.when you go to loosen the fuel return lines banjo bolted to each injector tap the allen into the banjo bolt a little they can strip out very easy tapping the allen into the bolt seams to help to not strip it out.Im sure henry has an exploded view under the creaturs of the night specs area can probably find the torque specs there as well.
Good luck Scott