You need to have the trans in neutral and the shifter locked in neutral, then adjust your rods.
You lock the shifter in neutral by putting a tool (allen wrench or whatever) through the "U" shaped notch and corresponding holes in the shifter levers.
The notch can be seen in your pics below where it says Hurst Comp Plus (and the patent numbers).
Neutral for 1/2 and 3/4 will be the center position. I can never remember about reverse.