I'd also ask what specifically you're trying to mitigate. There's a lot of bad information about some attacks and people thinking they're resistable when they aren't, such as the second tick of soul reaper (which many thought was somehow shadow/physical damage).
Soul Reaper does in fact deal Shadowstrike damage (shadow / physical), though I'm not sure if it's on the first, second, or both damage "ticks". The tooltip for the ability says something completely different than what the spell actually does, but it's simple enough to see in the combat log. However, as there is no physical resistance (unless armor counts as this?), there's very little to gain from discussing that particular spell.