The door bars have to run the way they are to pass at NHRA tech, just depends on the tech offical though, some would pass u, some would not.
Its whatever size tubing you have to have. Same as any other bar. I don't know off the top of my head. But the door bars directly would hit the armrest and the door would not shut.
Basically to be legal, the bars can't loop around the armres, they have to be the way they are. At my local track, things you can get away with would never fly at an NHRA track.