The only thing thats easy to screw up is if you try to unlock the barrel before removing the charge handle/rod....found that out the hard way. Just follow that website, its really step by step. I used a fat flat screwdriver with a set of vise grips on it as a bbl wrench, probably not the best way but it worked.
Can't speak for the headspace thing, not saying you shouldn't check it, but I know I never checked it and Ive ran a couple thousand thru it since with no issues.
After a quick google search, it does look like a fair amount of people recommend it. maybe ask a smith.
Duff