I'd have to crunch the numbers on it, but I felt it was safer to always sacrifice a relic to avoid having to make a travel test, rather than risk the X/6 followed by 1/3 chance of a test target number increase. The chance of X/6 followed by 1/6 chance of test target number decrease didn't seem high enough to reward investment, even with the Traveler talent.
Anyway, I'll probably give it some more tries later, though probably with "loaded dice" to pick my HP, missions, and one specific dungeon from now on, haha.