I have 3 struts. I'm interested in the model you're using? As I said, I'm having trouble thinking in terms of "if I shorten this tendon, it will effect everything else like this..."
I have 2:1 mechanical advantage on two of the side tendons and 4:1 on the third tendon (by going back & forth between ends as in your video). Tightening them a bit didn't seem to make that much of a difference, so I didn't try to set up anything more rigorous, but if you say that's the crux I'll give it a more serious try - thanks!