Next step here--taking Michael's model--simplified.
To get a net force up of 600 lbs on a given wheel, caused by the tension in
the top half being vertical but the bottom half at an angle theta (from
vertical), then I get that 600lbs = Tension(1 -cos(theta)).
At 10 degrees, you need 39,000 lbs of tension!
At 20 degrees, about 10,000 lbs.
At 30 degrees, about 4500 lbs.
I don't think the angles are 30 degrees (10 maybe) but can't imagine that
the sidewall tensions are high enough. I know this is maybe too simple, but
the basic question here is what magnitude of tension and what magnitude of
angle are needed for this to work?