Trailstar at the back is extra drag for marginal gain IMO.
Trailstar front, Pacestar back is standard for a reason.
FWIW, I’ve done Ardrock a couple of times on Snakeskin Evo Dampfs with no punctures. I only flatted the year I was using tubes because of rims that wouldn’t tubeless easily. Bear in mind the extra weight of the SG casing over the snakeskin evo is probably as significant as the additional drag of a TS rear.
That said, I’m running the WTB ‘Tough’ casing which is the same idea as SG on almost everything as standard right now – Vigilante Tough/High Grip and Trailboss Tough/Fast, so I shouldn’t really be talking about heavy tyres… 😀