I am familiar with the six harmonies
1. hand to foot
2. elbow with knee
3. hip with shoulder
4. (Yi) Mind
5. (Li) Body
6. (Chi) Energy
Yes I used to study how sounds, organs and movement were related. Not so much anymore.
Double weighted is real simple for me. 50% - 50% weight distribution on each foot. Put a plum bob under your perineum (inseam) and see where it falls. If it is in the middle of your stance, you are double weighted. Shift to one foot, if the plum bob is truly over the line of your ankle, your are close to being single weighted. 70% - 30% weight distribution is still double weighted. 90%-10% is functional enough but still not truly single weighted.
Below are a few ways I express unity of motion expressed in small circle and martial context. They will be up on Youtube for only 2 days.
Aiki Sword Drill Level 2
Small Circle Throw
Small Circle Throwing with Empty Hand