Bench seat adjustment

66 dart 270, has bench seats. I can see there is a lever on driver side, and beneath the seat it connects to a lever on the passenger side with a long wire. I can slide the seat back n forth but it is very difficult, as the seat doesnt stay straight so then it is cockeye.
My concern is trying to get it as far back as possible, and my knee still hits the shift lever on the column? I am 6'3". Is that the best I can do?

And on that topic, will the seat come out easily or do I have to remove bolts or rails?

thanks for any ideas.
Did you ever resolve this issue? I notice no one responded to your post. My seat on a 71 demon is not wanting to go back and forth. I have the body service Manual that does not address adjustment nor repair.
Thanks,
Al Graham.