R3 Lava Skip with hitboxes, video courtesy of DevilSquirrel as usual! I'm fairly confident his preferred technique is WITHOUT the stick being neutral, suggesting he is probably going slower than you could with a neutral stick (glide bashing).
It looks like skipping the 2nd wall is essentially pixel perfect given the method used by DevilSquirrel, Ori is moving BARELY more than a hitbox per frame, which is essential to skipping outside the hitbox between the frames. Hence, more speed = larger window, if you're going as slow as DevilSquirrel though, the window is going to be close to 1-2px or so, which means the trick is going to be very hard to get consistent. So here's to hoping that "fast bashing" gives you more speed.
Frame-by-frame: http://imgur.com/a/5KhQu
It looks like skipping the 2nd wall is essentially pixel perfect given the method used by DevilSquirrel, Ori is moving BARELY more than a hitbox per frame, which is essential to skipping outside the hitbox between the frames. Hence, more speed = larger window, if you're going as slow as DevilSquirrel though, the window is going to be close to 1-2px or so, which means the trick is going to be very hard to get consistent. So here's to hoping that "fast bashing" gives you more speed.
Frame-by-frame: http://imgur.com/a/5KhQu







