Miriam,
Hoppe's #9 is not that bad. Been using it for decades. It's mostly kerosene. It will not eat cured paint and it will not curl plastic. Many guns parts are made from plastic too.
Cowbelle,
To change the cam settings you have to PUSH IN on the outer knob and PULL OUT on the inner knob.
DO NOT FORCE THEM. They will only move one at a time. You have to set one, then the other. You can't move them both at once. If one control knob isn't completely set, the other will bind when you try to set it.
If they are sticking put the Hoppe's on the two posts to the left of the cam stack, they are where things hang up most of the time. Each post has notches in it and spring loaded catches that lock into each notch. These need lubed and cleaned to move freely. Get in there with tooth brushes or something similar and clean all the notches out.
You need to get that cam stack out of there too. That will help with the cleaning.
(( I just checked our 401 to be sure of what I was posting and the controls are sticking. Gotta lube it a bit now.))
Time to quit being timid with the solvent, get it in there and keep wiggling and moving things.
Joe