Am I missing something? Alignment problem

[nicks67camaro]

I loosened the allen screw to level the unit on the floor, and used the black knob to keep it in place. When I do this, the allen screw won't go back in. After re-leveling it again, it's now almost at 0(when attached to the wheel), and I haven't changed any shims at all. If I set it at factory 0, I am then at almost 2' on the car. I am trying to line up the center of the bubble with what reading I want correct?

I tried the same thing when I first got mine. When the allen head bolt is screwed in the tool is a true 90 degrees. If you are not on a reasonably level area then make it level (you can use a 6ft level laserlevel ect. I like to use sections of lenolium floor to shim the car level. once you establisted the car is reasonably level then screw the allen head in all the way then put it on the tire. this will give you your true camber setting. If you think its not accurate of your still way off use a small cheap level (one with a vertical bubble) across the rim and see if it leaning in or out. I am fairly confident that you'll have a negative camber reading with the allen head all the way in.
here is a quick and dirty on how I do my at home alignment (over 5k miles and not issues)

(all needs to be done at ride height and full weight of car ie hood / fenders / engine ect

1. use cardbord / lenolium or other low friction under tires to keep binding/friction to a minimum (and keep the car level)
2. roll the car back and forth to get the suspension unloaded (not sure if really nessecary but I do it)
3. Set you caster first (being mindful that you will need to add or take away shims so I start 2 shims in)
4. Camber is easy just add or take away shims till your reading is on. (just rember to add and subtract from each adjuster so you are not changing your caster.
5. recheck Caster (if you have a machine reading then you may not need to do this)
6. Set Toe making sure your caster / Camber doens't change
7. If "6" changes then just make minor adjustments.