Current limiting range on LM723 (from 0 to 5A)
The current limit function of the 723 is fairly crude to begin with. The &quot;reference&quot; is fixed; it's simply the forward drop of the BE junction of an internal transistor. Therefore, if you want an adjustable limit, either the series resistance itself must be variable1, or you need to put a variable gain stage between the sense resistor and the 723.
At this point, you're really starting to go beyond the kinds of applications the 723 was intended for, and there are far better solutions on the market today.

1 That's how I did it when I built myself a little bench power supply back in high school (mid-1970s).