Jabba,
Champion provide both a tool and a procedure for gapping fine wires see here:
http://www.championaerospace.com/ass...nical/93-2.pdf
There may have been some misunderstanding in my last post, i thought you were advocating for annual only on private aircraft with engine monitors and fine wire plugs hence my comments regarding eyeball inspections and magnetos.
The mention of magnetos at the start of your paragraph on plugs led me to believe that you felt plugs were sum of ignition system maintenance.
I have never had a problem with massive electrode plugs gapped
properly every 100 hours, although few do this properly.
Unfortunately you seem to be conducting the tempest resistance check on champion plugs. This test works fine on tempest plugs which have a ceramic resistor (linear resistance). Unfortunately champion use a silicone carbide resistor (not carbon pile as suggested by Tempest - true carbon pile were phased out in the early 90's).
Silicone carbide resistors are generally NON-LINEAR in resistance and optimized for resistance at operating voltages so they would need to be tested at operating voltage/conditions.
Champions advice here is simple if the plug is making a proper spark when tested in a properly calibrated (there is a procedure) plug tester then the resistor is doing its job. Using the tempest procedure on champions is just wasting potentially good plugs.
http://www.championaerospace.com/ass...ical/72-10.pdf (yes this is old)
Incidentally tempest based the resistance value on the spark-plug MIL-SPEC, since the mill spec is a production standard this is hardly appropriate for maintenance. (Like maintaining your aircraft using the original build specs instead of wear limits). The last revision of the MIL-SPEC was 1990 and it does not include iridium plugs as far as I can tell.