The adjustment I was referring to is the clevis and locknut on the end of the booster shaft that attach to the pedal arm That you are comparing a length of in the photo.
Don't measure or compare as you are with the level though, what matters is the distance from the firewall mounting surface...
You're doing it right.
There's also a free play adjustment on the rod that connects the pedal arm going into the booster.
It is accessible underneath the dash and is self-explanatory. I usually take 99% of the slop out of it and just leave a little eighth to quarter inch of movement in the...