Different wot rpm numbers

Hi all, I wanted to figure out my WOT rpm since I know the prop I'm running seems like it could be over revving motor. I picked up a tachometer that wraps around spark plug wire. So on bottom cylinder I was reading 480-510 rpm at idle and 2890-2910 rpm at WOT. I swapped plug wires and on top cylinder I got 690-720 rpm idle and 5920-5930 rpm WOT. Any idea why the difference between cylinders, coil going bad? My manual says 4500 rpm for EOT which I thought sounded low for a 2 stroke? I have a 82 Johnson 35hp J35ELCND. I'm looking for more hole shot and stern lift so I'm trying to figure out my starting point as to how the motor is running now before I jump into changing anything. Any input would be appreciated thanks.

those inductive tachs settings are a problem, for lawn movers to v8's, play with settings, hope your testing on the water, high rpms on a hose is dangerous. 5000 to 5500 is common for most if 5920 turns out to be correct your getting a good hole shot.