A 1921 "armored cruiser"

I've started the design process for a 1921-style "armored cruiser". I am experimenting with an armament of 9-9.2in/50 and 6-4.7in/50 guns. The side armor, initially is 6in. I'm not sure what power or anything else would be appropriate. I still like 32 knots but could live with 31 knots. I must not have a 9.2in/50 gun defined, as I got the usual "not-a-number" result for metacentric height. That is a sure sign of an undefined gun. I ran the gun program to calculate the muzzle velocity for a 50 caliber 9.2in gun (I'm going with 2,900 ft/sec). The preliminary dimensions are 721ft x 84ft x 48ft depth. The draft at normal load is 26.4ft. Design is an iterative process, and I don't have an inboard profile, yet, so this is very preliminary. My belt, amidships, is 7.5in KC, 16ft wide (two decks high). My designed speed is 32 knots at normal load and 31 knots at deep load. I'm hoping for a maximum cruising range of 10,000 nm.