Hmm. I see where you're going with that spring model. But what about this?: For a given spring, the force exerted goes up with displacement. So, to compensate for the DS forces, half as many NDS spokes would have to stretch twice as far. This means that they'd be exerting twice as much force, and would resist loads twice as hard.

I guess we could look at it this way: If you and I are holding Pcad up in the air, and you're doing 60% of the work, what do you care if I use one arm or two?