Here are two retail companies ideas to solve the width issue .
These are 70-81 F but the set up would be nearly identical
Those center steer racks had enough trouble as I recall with wear .
Now lets pry away at those two inner mounting holes by putting that bar on there to relocate the inner pivots.
I find it hard to believe you would not see issues with keeping that bar shifting and the hardware not keeping it in place if you really drove the car hard.
This one they have addressed the rack shaft from rotating and killing the pinion by clamping a pair of rollers to the housing to guide the center link
Lot of stuff going on when a rack was supposed to have less parts and more direct action.
I really find it hard to believe this stuff if going to give a benefit over a racy dephi ( or a well done Saginaw 800) box ,
frame horn braces, and a precision idler and center link.
NOW , my comments above are opinion only as I have never used or tested the two above racks in anything.
I have removed a couple of HORRIFIC Mustang professional rack conversion kits that were same kind of deal .
Feel free to agree, disagree, comment.
You wont hurt my feelings .