This is how we are attaching the shifter linkage now.
Before adjusting the two upper rods to length you will need to adjust the cables so that the rocker arms are straight up and down when the transmission is in neutral.
You may need to cut some of the threads off of the cable ends if it will not adjust short enough.
Leave the transmission in neutral while adjusting the upper two rods.
Set the length of the passenger side rod so that the lower part of the shifter handle just above the big pivot ball is straight up and down. The top of the shifter handle will lean back a little as shown below.
Set the length of the driver side rod so that when the shifter is relaxed side to side it will attach to the rocker arm without moving it.
These adjustments were all done while the transmission was in neutral.