I guess there's a reason why I don't post on this forum all that much. To me a lot of these posts are like the Gary Larson cartons when someone is talking to a dog, "blah blah blah blah epic blah blah blah blah epic". Bottom line is I really dont care vertical relative to what, as long as it works in getting something better from my turn. I hope to explore this in person with Jeb this winter, but have been working on it a little more myself and find it much easier on some of my skis than on others which makes me think that ramp angle is important to success here. Also, reaching shorts don't take much time to happen, so I feel like in a good one, the vertical femur movement begins at transition as the hips move across the skis, but by the time they reach vertical the skis are away from the body and carving down the hill. So vertical to what indeed. Like I said I don't care as long as I get a better turn from it. Feel free to discuss the minutiae anyway.
FWIW - I found this easiest on VIST X-FREE with VIST binding
easier on Nordica Top Fuel with Marker XBi
nearly impossible on Dynastar Contact 11 with Autodrive Fluid and Look binding (ordered toe lifters to experiment with this and see if it is the ramp angle or if I just sucked that day)