This is what is nice. No need to add linesman loops.
If you have a sit drag belted around your waist already... it makes for nice, big, in perfect position linesman loops.
Then you just use your linesman belt as your adjustable bridge for your sit drag.
Linesman belt off
Unclip tether biner from belay loop and slide biner up tether
Attach your backup prussic to tether rope (lower than main tether biner) and then clip it into the belay loop
Now you can tighten up that connection and release your linesman belt to bring it over the tether and clip into opposite sitdrag loop and now your linesman belt is your bridge.
Just clip it into main tether biner and adjust pressure off your harness backup connection
A couple ropemans make it quick work...tedious part is dressing the backup prusik