Two safes are always better than one, logistics if nothing else being the reason. Mr. burglar may be torn between the two. Two take longer to get into. Mr. burglar has a 50/50 chance of getting into the one that you value the contents most. Longer time in your house means more time for him to get caught in the act, or seen, or shot by homeowner.
I have wood floors and my safes are heavy (one is 680 empty, one is 775 empty). I went up 16 rungs of stairs to go upstairs with the 680 model, not even a hiccup. Used a large dolly and 4 men. Took about 10 minutes to go up the stairs (we did a lot of resting). Modern staircasing with 2x10 framework is very sturdy. We put carpet on the flooring to keep it from getting scratched up. Put the carpet side down.
Another tidbit of advice I received and heeded. It's kind of a common sense thing, but don't put safes next to a window. One they can be seen easily and the other reason is mr. burglar can wrap a strap/chain/cable etc. around your safe and pull it through your window with large truck/tractor etc. Hey, it made sense to me. I don't want to help them in any way. Anything can be broke into.