Mount them as vertical as possible without the shocks limiting your articulation. (and mounted out as far as possible on the axle.)
I believe what Mike and Simp are getting at is given the SAME shock, it will allow for more articulation if tilted /\. But if a shock mounted || isn't limiting your articulation, there is no reason to tilt the shocks inward.
I would rather buy a longer shock and mount it || than tilting my shocks /\. If it can not physically fit where I want to put it, I would compromise and mount the shocks as vertical as I could without limiting my travel.
