When I find my rhythm is off or otherwise need to work on my lower body I often practice throwing standstill with putters and mid ranges. I work on throwing with only 75% or so arm/upper body speed and getting distance out of my weight shift and push from the back leg instead of my upper body motion. I find that it's a lot easier to really get a feel for your lower body that way.
Once I get comfortable doing that with consistent results I'll speed up my arm for a couple rounds of throws and then eventually work back into the full run-up.
In a way it's similar to the method Dan Beato is teaching in that video. It tends to work pretty well because it's a lot easier to make changes at 75% speed with less moving parts than it is at full speed. As an added bonus, it's good practice for standstill touch shots because it's basically the same form.
Practicing in a similar fashion might help you bridge the gap to the new technique in you lower body. I find that in both ball and disc golf it's a lot easier to take baby steps like this than jumping in and trying to get the whole motion right immediately.