it does seem odd that a 275 wide rim on a 9 wide is perfect when a 275 is 11 inch and the rim is 9 inches seems a 245 would be perfect dont it? well its a horrible fit, a 245 on a 9 wide is far to narrow.
so you see thats not the way it works... if you go 295 it might be ok i mean you will still curb a rim sonner or later cuz the tires wont be wide enough to protect the rim. If you care about your investment you will get a 305 at least, if you dont want a 305 then you SHOULD NOT HAVE PAID FOR 10 inch wide rims and you should sell them and get 9 wide so you CAN run a 275 you dont buy staggerd size rims and run the same size front and back...
they will look awsome if you run a 275 on the front 9 wide and a 305-315 on the back 10 wide you wont be sorry a 305 should look great and protect the rim a 315 will for sure.
Im just trying to help you out so you dont make a bad move on what tiers you get and you regret it for the 3 years you will have them on there~ and i would hate to read a post where you curbed the rim or your tire pops off from being stretched to much and goes flat and you get in a wreck or what not.