Alright I've finally got into a position and a house that I can install a safe  I plan to do so in the barn/shop in the back yard (fully insulated and climate controlled and on a slab)

here are my questions    I have a bunch of guns and other things I want to store  Do I want multiple smaller safes (20-28 gun) or one large safe (40+ gun)  The long guns I am storing would be split about equal between fud guns and EBR's  

In looking at larger safes I've looked at the sportsman steel safe, the rhino metals, the ft knox, liberty and a few others on google   Who would you go with and why?

I want something with 90 min fire rating minimum for document storage, adjustable interior, pistol storage, and electric locks

Sportsman offered me a 72x46x28 in black gloss with a concrete liner and electric lock for $3800 delivered   any opinions?  would I be better served with a ft knox or even going to a multiple small safe setup   Price is important but I also don't want to regret going cheap later down the line

I'd go with multiple small safes rather than one big one. Several advantages:

-all else being equal, it would take longer for a bad guy to defeat two safes vs one safe
-fire protection. Put 2 safes on opposite ends of the building. Won't help in a total burn down, but if a fire starts on one end of the building, there's a better chance at least one safe will survive.
-lock outs. In the event your lock fails (unlikely, assuming a good quality lock, but still possible) you'd still have access to the stuff in your other safe.

One downside is that two smaller safes will likely cost a little more than one big one.

As for other brands to consider, there are a lot of people on here who like Sturdy or Amsec. Look thru some of the threads here, and you can learn a lot about the advantages and drawbacks of each. Also, you mention that the building is on slab, so I'm guessing that weight is not a big concern. You might want to consider a used commercial safe. You can get a used TL15 or maybe even TL30 for the same or less money as some of the better RSCs, and have much higher level of burglary protection.

1. Don't put all your eggs in one basket.

2. AMSEC.