Why do you want to adjust it? What is the voltage at? (You are OK from 0.5 to 1.0 V at idle)
I know that on my 95 TPS the screw holes had a metal sleave and you could not adjust it all that well.
Otherwise enlarge the 2 holes in the sensor ever so slightly and turn the TPS so that it increases or decreases the voltage.
While many here will say to get the voltage close as possible to 1.0 V in my car, there is no difference between .80 V and .98V. I recommend that you just make sure the voltage is between 0.5 V and 1.0 V.
Just my take
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1995 Mustang GT