Looking good! Nice AR recognition.
Make sure your hand controller is attached to your camera (either one, but not the parent of these), This will remove the jitter on the hands I'm seeing when you move.
The position of the hands is usually a little offset from the center of the camera (as your hands are not where your eyes are, they are down and forward a little bit, on DK2 I can adjust this live, but on cardboard might need a little trial and error)
The video feed is unfortunately monoscopic on a phone, and usually off center, not necessarily where you eye is, so adjustments will need to be made here, and the IPD offset is usually about .063 for most people to run stereoscopic feeds into the virtual cameras. Looks like you've got the hand scale pretty close, but as you adjust position, you will notice scale sometimes gets affected relatively. Between the position and leap scaling you should be able to get a pretty close 1:1 with your real hands. The trick here is that the feed is likely not 1:1 with the scale of the real world and how you perceive it. So scaling the feed quads will fill your viewport, but leave you with a magnified world, actual scaling will leave you with postage stamp like feeds in the headset, but this at least is not disorienting, just limited FOV on the real world. So find a happy medium here and you can benefit from some of the distortion provided by cardboard, or Oculus to extend the feeds through warping and increase your FOV without scaling up the feed quads. It looks like you have some distortion going on but it varies VR/AR, which is weird, I'd look for a happy medium here too.
Really awesome work you're doing, keep it up, let me know if you want to collaborate on anything, love this stuff.