I have run Champion fine wire plugs in my 0540 carburated engine for 20 years. Started using them to avoid fouling. I have proabably had three rough run-ups that were quickly cured by a leaned out 20" mp run-up. My friend who runs massives will occasionally take off with a fouled plug to clear the fouling. I don't like that idea at all.
Have never had to have the plugs cleaned between annuals. (~100 hours per year.) Have had one plug failure. It was a real headache because it would test good on the bench. Had to go to 8000 feet or above to get the miss. The plugs had 1200 hours at that time. Never new which plug of the 6 was the problem. Pretty sure the rest of the plugs would have kept going but have no idea if they would go to TBO.
My two cents:
Use fine wire plugs.
Change them at 1000 hours or if dropped
Overall costs will be pretty close to massives and they seem immune to the type of fouling which requires a return to the ramp.