Dimpling the barrel is the good way to go.

It's really easy.
Just install the gas block in the proper position and tighten one of the setscrews really tight.
Now remove the gas block.
You should have a nice little ring from the cup-point setscrew.
Center punch the middle of the ring.
Now drill into the center punch with about a 5/32" drill bit.
You only need to drill deep enough that the full width of the drill bit has begun cutting.
You don't need to continue drilling to the point that an actual hole appears.
You just need the pointed part of the drill bit to be just into the barrel.

Now re-install the gas block with the setscrew centered in the dimple.
That's it.