If the technique you are talking about is the one I think it is then you should end up coming out into a forwards flat fall.<snip>
I think Aviv Sensei is dead on the money. (He should be, I think he's soon to receive a nice shiny 4th dan certificate with Saito Sensei's signature across the bottom).
Ganseki Otoshi is something like koshinage. There are two differences in my limited experience. The first is that uke is more across nage's shoulders as in a fireman's carry. The second is that uke is face up rather than face down. It is a major-league scary throw to do at speed.
It looks to me like a dynamic version of the Daitoryu technique that one sees pictures of Sokaku Takeda Sensei with uke stretched across his shoulders. It's on the cover of Stanley Pranin's "Daito Ryu Aikijujutsu" book. If it works, here is a link:
I'm sitting looking at Saito Sensei's original "Traditional Aikido Vol. 4 Vital Techniques". Ganseki Otoshi is on the cover. You can see that uke is over Saito Sensei's head (i.e., about six feet in the air) and is rolling his legs up so that he can flip over and land on his feet.
My hat is off to anyone that regularly lands out of this fall on forearms and live toes. OTOH, the Daitoryu version that I've seen windmills uke off nage's shoulders and uke lands flat on his back. Ouch!