If you have adjusting nuts on the end of your cable then your cable is junk (an opinion from someone that's been through some heavy clutches and a few cables). Ditch it before it leaves you stranded somewhere.
If you start leaning toward a FW adjuster, I would take at least a brief look at anything else you have in that area. Some intakes or other items can make them difficult to get to.
I personally like the Fiore Micro-click (not available anymore because reasons).
This is what is left of that unit:
uprproducts.com
It's pretty much the same thing except that the Fiore had larger/better knurls on the knob.
A tip that I got from
@jrichker many years ago: Put a thrust bearing underneath the firewall adjuster. It's an even better idea because of the locking feature of this particular unit. Adding the bearing between the adjuster and the firewall makes it smooth while the 'click' feature provides a positive lock to keep it from backing out.
Somewhere around here, he's got a thread showing some images. I'll post it if I come across it or maybe one of these other guys knows where it is off the top of their head.