You don't need a NOGO gage for headspace unless you are installing a NEW barrel.

I'd add to your list a "special" screwdriver (bit) hollow ground for the screw fastening the barrel band. While the screw was originally designed to accept a 30 carbine case rim in its slot, and it's sorta fun "reenacting", using a modern tool is much easier for routine disassembly/reassembly

HTH