You do not require a Kantrael shotgun to make the build truly work, as the Mk II Heavy Eviscerator is good enough on to hold its own against any heretics that dare to cross your path, though I personally reccomend any weapon that proves effective against close range targets.The lower your health, the more powerful you become.
Do not forsake a medicae station if your faith in the emperor starts to falter, weakening is preferable to death.
(Essentially prioritize corruption over health when medicae stations are present, as you won't be going down much if you play this right.)