I an planning on building a 10'x20' run using a party tent frame. I would like to wrap the entire thing in chicken wire and then run 36" high welded wire fencing (2"x 4" openings) around the bottom with 12" of the fencing bent out as a no dig barrier. The chickens will be cooped at night for safety.
Which is the preferable chicken wire for runs? 2" opening or 1" opening?
Definitely the 1" opening if you use it. The 2x4 welded wire will stop larger predators, overlapping that with chicken wire will stop smaller predators. Some critters like snakes, mice, and smaller weasels can still get through but a combined 2x4 + chicken wire is pretty effective, especially when combined with the apron as you plan.
Larger predators like a big dog or big boar raccoon can tear most chicken wire, how big they have to be depends on the gauge of the wire. Larger animals can tear some hardware cloth, again depending on the gauge of the wire. Wrapping whatever frame you use with chicken wire will provide a deterrent against many critters but not all. Putting 2x4 welded wire around the bottom will really help but raccoons can climb.
I built my run out of 2x4 wire and put a solid roof on it. Then I wrapped the bottom 18" or so with chicken wire, more to keep baby chicks in than any other reason. It has an apron. Practically anything that the 1" chicken wire will stop but that can get through the 2x4 wire can climb but the arrangement has worked well for years.