Since know one else want to make a *** of them thyself........uwh uwh pic me pic me!!!!!:lol:
From what i under stand of plug reading in the lower ceramic it is totally full throttle fuel and the thinner and lower the line the learner it is. So with that theory.
I say jetting, or power valve channel restriction need drilling out so that a jet can be installed to tune it.
It could be air bleed side of it too but just don't understand that stuff enough to even comment on it
as far as mid range and idle.....can't even guess on that.