We started learning this technique and I humbly submit this short clip of me performing ganseki otoshi. Any constructive criticism or thoughts are welcome.
I believe this is the correct way for the uke to land, on his feet. from what I understand any other way would be dangerous to uke.
As with Ron, comparisons would benefit you more than any criticisms I would make.
FWIW, I have a terrific video set from CoolRain, Aikido in Training, and UKE lands on his knees with this technique.
Isoyama's version is what judo calls KATA GURUMA, i.e., UKE's belly is on NAGE's shoulders, not his back, but naming conventions are quite variable.