'82 240D early shifting vacuum modulator adjustment ??

my 1982 240D auto transmission is upshifting way too early - I'm in 4th by the time the car is at 25mph. How much can I adjust the vacuum modulator to adjust this shifting? I recently replaced the VM because the car wasn't shifting at all higher than 2nd gear. The VM replacement fixed that, but now it's shifting way too early. i installed the VM as is out of the box. i know you can turn the key clockwise or counterclockwise, but i can't find any info anywhere about how much or how little. is there a spec that i should be shooting for on this?

also, on the VM that i removed, key was actually left in the VM, locked into place, under the plastic cap. should i be leaving the pin in there to keep the adjustment set in place?

thanks.