1. HPI guy uses almost the same method I use. I tighten the nut with armorer's wrench then just give the wrench a solid whack with my hand to make it tighter. Done.
2. Never staked a castle nut on any of my rifles. Never had one come loose but I also don't shoot 10000 rds a month or operate operationally in my area of operations (some here might actually understand that reference :ror
3. I've never read about a gas block needing staked. Are you using a set screw type or a clamp on type? I have set screw ones and I just use red loctite. Unless you are doing mag dumps constantly you probably won't get it hot enough to degrade the loctite.
If you are worried about it rocksett won't hurt but I'd make sure everything is functioning before using it. Most gas blocks will not sit against the shoulder on the barrel and if yours is the gas port is usually not centered in the gas blocks hole. Making sure this lines up correctly is important. Once rocksett sets you can't get it off without soaking it in water (or so I have been told). Heat doesn't work on rocksett which is why it is used for suppressor mounts.
4. If you are using a crush washer and a muzzle device that doesn't need timed you can tighten it down as much as you want. Usually you thread the device on until it hits the crush washer and then index it how you want it by going tighter. I believe once you start to crush the washer you have almost 2 full rotations before it bottoms out.
