I learned an effective way to stop the "twist" this weekend from a fellow classmate . . . he is much taller than I and he actually starts to kneel when he enters Shihonage . . . he still on very much on balance . . . there is NO way that uke can twist out, plus it is very gentle on the beginner uke because their center of balance has been thrown SO far out of wack that they are practically on the mat by the time the move is about 3/4 of the way over . . .
i am a beginner as well . . . as is the person who showed me how to kneel during Shihonage . . . but at the same time, we have many advanced students in our class . . . it is just a matter of respect that you do not criticize those with more experience/higher rank . . . sensei will take care of that