I know yours is an '09, but check out this wheel/tire thread (below) for ideas. Great info on fitment, rubbing, performance, balance, etc. as well as tons of photos. But be prepared, it might take you a few days to get through the entire thing. But its fun! I almost went down the rabbit hole again myself just now.
I've also attached a few photos of my 2010 with the Saleen Heritage (in charcoal that I picked up new for $450) that were originally meant for your body. They are 19x9 front (275s), 19x10 rear (285s). I've since added a black Ford oval to centercaps. IMHO, this is the perfect setup for the car, not too flashy, but still meaty, and nice performance/ride balance. Enjoy!
https://www.svtperformance.com/threads/official-2011-mustangs-wheel-and-tire-thread.845043/