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.
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If one could build a plane with, say, 90% of the weight right on the cg, it would damp faster than anything else. One could do something similar by adding lots of ballast but that kills performance because of the given thrust available. If Unlimited thrust was available, it would be a different conversation.

MOI is one of the main reasons (there are aerodynamic reasons also) I've developed my wing designs around a higher taper ratio than any one else is using. Getting more mass closer to the cg and less at the tips makes MOI sense. And aerodynamically, the design moves the AC closer to the fuse CL, meaning turbulence affects the wings less. Control efficiency is also improved.

I really want to increase taper ratio beyond my current 3:1 but I am hitting a wall on the foam cutting. It isn't insurmountable though. I suppose i could always build one from wood. One of these days I may get around to it. MOI is the reason I build stabs and rudders as light as possible and move the wing forward. The performance envope that these "apparently " small changes result in is quite dramatic

Dave, BTW, just pulled an 18x12 hybrid prop from the husks....50 grams after minor trim. That's for the gasoline engine. Yet another example of reduced MOI

MattK