I've posted before about the Jobst test - they only checked two of the three ways the wheel can deflect.

Plus, it would seem obvious that spokes that flex less will be stiffer, at least in one direction.

Jobst also says "Even a radially spoked rear wheel yields no perceptible compliance."

So tied 3x, untied 3x, radial rear - no perceptible difference between them says Jobst. And yet, if I was going to ride (the old) Ghent velodrome I know which one I'd opt for.