Shoutouts to Jaise and Kitcot for trying to get this consistent as well
Run up the wall near the ledge. The Z position should be a perfect -3076. Perform one perfect sidehop (Z=-2740) and 2 perfect backflips (still Z=-2740). To turn around and grab the vine, I press the home button, buffer holding perfect down on the joystick and + on the wiimote, and press home again to return to gameplay. This should buffer you turning around and bringing up the map. Stop holding down, unpause and press A ro grab the vine at Z=-2740. You can do this turn around unbuffered but it's actually rather difficult. Tap up twice (make sure it's perfect up), then hold right in the notch. Final Z position should be -2553.5769.