Re: 1,2 ,5 & 6 look perfect, but 3 & 4 are carboned minorly
This is pretty common for center-mounted 4 bbl. (the center pair has more demand because it's closer), but the real question is: is it also true at full throttle?
If you can get to it you can modify the floor of the manifold to reduce the amount of fuel entering the 3-4 with a shallow ditch across in front where the runner takes off from the plenum floor (and it's got to be squeaky-clean afterward). Use a Dremel and a 1/8" bit, and just drag it along the face of the 3-4 runner inlet.
This will allow even leaner jetting (they'll all run the same) by perhaps 1 jet size.
From your comparo of accel using 53 vs. 59, we know that you need more PVCR than you have. 59 may already be too rich, so try both ways at WOT for test.
Once you pin that down (using the wrong main jet to supply the extra fuel to calculate how much the PVCR has to go up) you can go back to the 53.
