What clown said about size.
I am a big fan of Johnson safes: 1. The welds are very, very strong. When I was a LEO my safe crackings that I saw were safes knocked over and then beaten on the top to break a weld and then peeled up like a sardine can. The commercial gun safes sold in sporting goods stores or gun stores are weak in this area (got to save money somewhere to pay for that elk scene); 2. Johnson uses a ceramic water heater insulation blanket, everyone else uses dry wall. Dry wall is gypsum and water. I do not like water around my firearms as it destroys them. The cermaric blanket crystalizes in fire and is purportedly rated to extreme temps (like if the rest of the burning house fell on it), but I do not believe it is UL rated; 3. He will build to your specs and deliver it to you (you do not list a location you clever tactical guy you, so I don't know if he will deliver where you are).
As other TFLers have said, first, hide the safe. With unlimited tools and time, nothing is unbreachable. May want to PM MPFreeman. My brother just re-modeled his basement and did a great job of hiding his Johnson safe.