Beginner questions about editing CC lines in GP4Builder

I noticed that CC cars were going through walls a little bit at a couple of corner exits on the Phoenix track in the beta track pack which came with Kerley’s 1990 mod. So I downloaded GP4Builder, watched a couple of videos on how to use the program, and studied the CC line in the .dat to see if the answer was clear to me. I did find that the CC line touched up against the wall at the exit of turn one, for example. Trying to fix this left me with some beginner level questions:

Before making any adjustments to the CC line, I tried watching the onboard video in GP4 builder, but the car seemed to stay in the center of the track instead of following the racing line. Is there a setting or error I need to correct so this will work? I tested a vanilla game track the same way and did not have this issue.

When I am attempting to have a 0 radius straight line go across the track diagonally (example: from exit of turn one at left of track to entry of turn two on right of track) I tried to modify the shift value since the end of the line was no longer on the track. Changing this value did nothing. How can I change the angle of a straight line?

I’m sure I’ll have some successes and more questions as I learn, but this info would be a huge help. The track is fantastic to race on, and I hope to make it just a tiny bit better with effort and your help.

Thank you.