I'm still checking in from time to time but currently rather preoccupied. Father had a stroke back in April and we're over in the UK caring for him since his discharge from hospital.
The pilot jet, needle and main jet influence on fuelling is cumulative rather than separate. As the throttle is opened, the needle profile and main jet size take precedence but fuel still flows through the pilot jet and the idle mixture screw setting still has some influence on the a/f ratio at mid-full throttle.
I found that if you tend to ride mostly on part-throttle and keep the revs below 6-7k rpm then the plugs will be more likely to show blackish and there will be some sooting around the exhaust outlet.
Although Ivan recommends 4.5 - 5 turns out on the mixture screws, I settled on 4 - 4.25 turns after a few years of doing his kit installations. Ivan also says it's optional to enlarge the second bypass hole. I favoured just enlarging one hole - it didn't seem to make any difference on performance but reduced the tendency to run too rich at idle.
While plug colour is a guide to fuelling, it doesn't tell the whole story. Anyone who remembers doing plug chops on 2-strokes will understand what I mean.
The plugs in the OP's photo are much like mine were and I would call them typical of a Full Monty installation. You could spend time and money on a dyno trying to fine tune the mixture screw setting but I suspect it would make only a marginal difference. Is it worth the hassle and cost to strive for an ideal a/f ratio at the very bottom end of the rev range/throttle position? I don't think so.
Cheers!
Mike