spark plug grade and plug chops

[bluebob]

couple of questions about the above.
for an example.say you do a plug chop using a cold type plug then note the plug colour.replace plug wiih a hotter grade plug and do exactly the same plug chop.would you expect any difference in colour?

probably a more important question,testing main jet range as example.Been running in ,nice and rich.plug jet black.go leaner for next run.to get best reading is it advisable to give the plug a quick clean,or is the effect of changing the jet so instantaneous that it doesn't matter.or do the experts carry a few clean and preset plugs with them.any thoughts please.

[hullygully]

don't clean the plug till after all your chops, you must do about 1/2 a mile @ constant speed to realistically change the colour

[bluebob]

cheers mate.
will take your advice on that.