It depends on how you intend to use it. If you are going to be doing most of your shooting off hand, then I would start that way. That would seem not to make any sense, but piston guns can be hold sensitive, some will argue this point, but I always say it depends on the gun, some are some, and are much less.
However, if you are going to be using any kind of a rest, be it a tree limb, or a back pack then sight in that way. Always put your hand between the surface that you are resting the gun on and the gun itself. This will make it shoot more consistently.
Now, comes the hard part, some barrel cockers have a lot of barrel droop and you actually have to buy mounts with droop compensation built into them, or adjustable type mounts. Which to buy is up to you. Try regular air gun mounts first, if you can get zeroed your doing great, otherwise you will have to get the a-for-mentioned adjustable, or drooped mounts. Now, that was a mouth full.
You also buy a dovetail to weaver conversion mount, and use Burris signature mounts, I like these the best, they leave no ring marks, and while it is a bit of a pain to do so, you can just about zero the gun without touching the scope adjustments.
Hope this helps…… as all this talking is leaving me short of breath.
Jim