I've never done it, but that is going to be a PITA to reach. Not saying it isn't possible, but that spark plug hole is hard enough to reach just to pull the spark plug out, let alone to do a repair on it.
As far as being recommended, I'm not sure. If you don't remove the head, you're going to be dumping tiny metal shavings into the cylinder. most likely they'll just burn up, they'll be that small, but they may not.
