no matter the plug type, you shouldn't gap < or > .008". The reason for this is the ground electrode and center electrode won't line up properly, hindering spark plug performance.
The manufacturers say you should not gap iridium plugs. This is because most people do not know how to properly gap a spark plug, and the center electrodes on the ultra-fine iridium can easily snap if mishandled. There is no warranty for snapped center electrodes. The manufacturers say an iridium spark plug will run so much better than a traditional plug, even if it is not gapped for that motor, that they would prefer you just leave it rather than risk snapping the center electrode.
Here's instructions on properly gapping:
"If it iss necessary to widen the gap, do so with a tool that only pulls back on the ground electrode without touching the center electrode or the porcelain. To close the gap on a plug, gently tap the plug, electrode first on a hard surface." (taken from sparkplugs.com's "sparkplug 411" page)
Scotty's 100% correct on the "-11". Start with the non"-11" plug and this will minimize or eliminate the amount you will need to gap.