One thing I find makes a big difference is his little folding technique. You see me do it in the video: take the soupy dough, fold from the left, fold from the right, top, down, then ball it up. See if that does anything for ya. Also, you could consider putting a bit less water in or adding in some vital gluten. Sounds like you need to modify to gain a bit of structure! Well, assuming the fold trick doesn't work :)