What you are molding is the self adjusting mechanism present in every drum brake e brake handle. So if your stang had drums, you should do the mod. The prob with the self adjuster is that it is always active. It has the potential to adjust when you don't want it with the disk brakes and tighten up the cable and drag or lock your parking brake. What you do when you mod this is lock the adjuster on one tooth.
Sn95 handles are different. They have a stopper which defeats the auto adjuster from adjusting all the time. The 99+ mustang even had a recall because the stop would fail and the parking brakes would drag.
The reason for the drag depends on the cables. The 1993+ cables are fully covered and have more friction, so they are more prone to not fully release which causes the auto adjuster to take up slack. The pre 93 cables are mostly loose and free, so they have less friction.
So what you do for the parking brakes depends on what parts you use.
I am currently looking for a leather wrapped cobra sn95 handle to mod so I can adjust the tension from in the car rather than crawl under,