Node connector points calculate nicely and without unnecessary overhead (my first pass on it was embarrassingly poor, so I immediately redid it). Worked first time, too - I always feel a bit suspicious when that happens :D
I also turned on Box2D's Continuous Physics mode because the change in physics scaling has led to some rather unfortunate tunnelling issues with the axons and the bucket. It has had a really crippling effect on the framerate, quite pathetically so in fact - under 30, in a game that consists of nothing but circles and lines!
So I set up Release Mode and was gratified to get a stable framerate well over 120. Well, that's something at least. Picking still doesn't work right, I need to completely remove the ScrollComponent and bake my own replacement (which should hopefully fix pinch-zooming in Android and the weird scroll wheel problem under Windows, as I think it's ScrollComponent that's causing both issues), and that's a big job, so with the school run rapidly approaching I've decided to leave that for next time.
Still, though, a hell of an afternoon's work.