Takashi-san explained to me that for jujinage, you would ideally want Uke to go head first into the ground. We of course let him roll out for safety reasons. So, thinking this way, when I am about the throw Uke I should do it in such a way as to cause his head to go down to the floor at his shikaku. This helps him to roll as well because if his head is close to the ground then his body will be too for an easier ukemi.