The funny part is, I don't have to. My position is based on facts. Your position is based on your gut feeling and supposition. You are the one who needs to prove your stance, not I.
"(hypothetically) the Emperor were to die of a heart attack, you're thinking is that Tarkin would become Emperor and Vader would still sit there all the while thinking: yes I could force choke this dude, and yes I an the 'chosen one, but I better not since Palps liked him? Correct?"
"What-ifs" don't do the job. This is mere reasoning, not proof. Lucas wasn't concerned about such "Chain of Command" questions when he wrote the film. He put Tarkin in for a very specific reason - to temper Vader's character. Your question has nothing to do with the scope of the films. Hell, we don't even know if Tarkin is the only person between Palps and Vader. Fact is, neither of us know the answer to this question, and never will, so it's a waste of time trying to answer it.
Furthermore, I never said Vader wouldn't take out Tarkin. I simply brought up that quote because you believed the only reason Vader didn't take out Tarkin was because Palps was "protecting" him. Seems to me Vader has some respect for the guy - you know, the one who calls him "friend"? As far as the first novel goes, Vader worked under two men less powerful than he, The Emperor and Tarkin - something that apparently does not make sense to you.
Lucas has said Tarkin was above Vader. You don't like it? Tough. Go yell at Lucas about it.