1980 kz1000 uneven mix across carbs

hi again, in process of rejeting my z1000 it has vm 33's marshall 4-1 and pods, stock main jets should be 127.5, to begin with it had 115's and was obviously way lean, im now back 2 127.5's with needle in forth positioon as a start point and have found as expected these are also 2 lean ( have been told to expect to go up 5-10 sizes for my system)
however after doing plug chop ive found that plugs 2 and four are sooty as hell ( 1 and 3 are lean as expected)- i know its not down to the ignition system
could this be down to anything other than the carb setup, im hoping its something simple like float height, plug chop was done after about a mile run with the throttle as full open as possible ( running like shite at high revs some lean some rich), once again any info/tips much appeciated.....

New jets might be mislabeled. It's happened before.
If you haven't, you might want to check compression before tuning.

hello, replacement jets are not mislabeled and compression feels v.strong with finger over plug hole,
could float height effect mix that drastically, or any other ideas ?.....