Tried to send these to you in a PM, but you can't actually upload pics in PMs
The rears are Duratracs in a 215/85R16, That's a 30 Inch tire, as are the 245/75s you currently have. If you want to go up to a 33, I think you're going to have to go with some real pizza cutters to fit on the rear duallies...
The Duratrac doesn't come in a 255/85R16 Which would be about the biggest I think you could fit on the dually rims.. The BFG KO2 Does... Which was on your short list...
The Closest the Duratrac comes in current sizes I could find is a 235/85R16, which is a 32" tire, and a good size I think.