The plastic front sight "A frame" block is a good investment so that you don't have to bang the barrel on the side of a toolbox in an unsupported fashion.

Barrel nuts are to be torqued a minimum of 35 ft/lbs and a max of 80; no need to go to 80 if you don't have to.

You also may want to incorporate timing the gas tube into the gas key. Helps accuracy and reliability.