Not sure about the Z71 wheels, but my Trail Boss wheels and DuraTracs worked excellently with a 1.25" spacer. No lift or leveling kit.
Only rubbing I am getting is at full lock there is some against my WeatherTech mudflaps. Not enough to be of concern though.
With my DuraTracs and factory flares that put the sidewall of the tire just out beyond the flare. I didnt want to get beyond teh fenders as I dont want crap thrown up off the tires onto the side of my truck all the time. I ended up having mine powder coated black so they were less noticeable behind my black wheels.
The key is to check the backside of your wheels and see if they are grooved or indented all around...this will allow the ends of the studs room to sit without having to shave them off.
Red Hot Trail Boss