Thanks Dave. This is some of what I was trying to figure out.

1) I've heard the 'barbell' analogy before, but to me it almost makes sense to have the weights spread out with the result being increased stability; it would require a more deliberate input to get the plane to pivot. I'm probably wrong and missing something, but it just seems like a centered mass would seem more 'tipsy'.

2) I don't know anything about the efficiency of pull-pull vs. efficiency of a pushrod.