One thing that I have not seen mentioned is once the safe is in place, bolt it to the floor. In my case, they sit on a concrete slab. Holes were drilling into the slab and threaded bolts epoxied into place. We used a special type of epoxy made for that purpose. IIRC, we got it at Home depot along witht he threaded rod. We gave the epoxy 48 hours to cure, the placed washers on the threaded rod which were then tightened up using more epoxy on the threads to more or less make it permanent.
If you don't do this, all a burglar need is a decent dolly and away goes the safe and the gun collection.
Paul B.