Tire & wheel package

[seabass]

New to the site. I have a 2015 bighorn 4x4 and am looking to do a wheel and tire set up. It has 20x8 with 275 60 20 tires. Not sure of offset. Was looking into 20x9 with either the 285 65 20 or 275 65 20. Want a slightly aggressive stance. No more than 1" past the body if possible. Will these tires fit and what offset do i need to achieve this. Thanks for any help.

 

[ruskibrewski]

Are you going to lift it all? Perhaps put o a leveling kit and you can go as large as 35's.

 

[seabass]

I would like to stay stock for now if possible.