Avalanche Tires What Size Tires For My Avalanche?

What size tires for my Avalanche? - avalanche tires

I have a 2005 Avalanche Z-71 with wheels 20 x 9 and I make some all-terrain tires. I'd like the meat and aggressive tires, but I'm not sure the correct size. Am I to 275-60 with 285-50 R20 or R20? What would my car look mean?