I have unfortuantely (fortunately?) not thrown a 56lb yet. We have a 40 lb heavy weight for distace but that's it. Difference between the 25 and the 40lbs is only 15 pounds obviously but the amount of force it generates and the potential it has to throw you around dramatically increases.

For the LWD I use two spins, but for the HWD I just go for one. It's just too much weight for me to do a double spin with. I definitely agree with your assessment though of drastically slowing down with the heavier weights and just focusing on holding on to it, and releasing it without falling to the ground. The form and distance will hopefully eventually follow with enough practice.