Thanks, its much clearer now. I'll still need a bit of time to process the data, but I really like your test rigs

about the piston thing... I just did a reconfiguring continuum to test a concept and it seems to work (but only for anchored application because of phantom forces

). Have two continuum each attached to to a solid attach point. Then, attach both of these to a third part (can be a fin if you hack map files, must have at least two attach points otherwise) but do so in a way that the two arcs conflict with each other on what the position of the third part should be. Now, by setting one of the continuums's mass to 0, you can weaken one of the connection and give near complete authority to another, thus changing the position of the third part. This seems more rigid than pistons, but again phantom forces...
This might not be useful for prop planes, but there might be some applications nonetheless.
UPDATE: the technique itself seems useful, but a big problem is that when saving, any stress in the voltaic arcs is relieved, which stops anything from functioning. My bigger worry is about how map files works: I'm not sure its possible to create a feature like that even using manual file editing. Even just being swallowed by an hypercube then spit back cancels the effect