Rich or Lean?

If I may add my humble $.02,
mixture distribution may be an issue, but before I chased that
I would correct the plug gap and center electrode to ground
electrode alignment.
(forgive , I suck at paint files, so verbally I go)

first pic, compare plugs #1 & #2 (ground to center electrode alignment is way off) also gap on #3 looks short.

second pic, #2 ground electrode looks "bent" off center from
pos electrode. #4 looks (maybe camera angle) like the gap is long.

lastly, all the ground electrodes
show a fairly even heat transfer.
and the nice tan color ...ist goot..

hope the verbal visual makes sense.