Re: uke spinning out of shihonage
If they spin our of your shihonage, imediately do the technique again, they will likely try and get out the same way. If they do that, just stop turning, and let them do the work for you.
Uke is turning the same way as you do in order to "turn out" of shihonage. If you keep turning while they are it makes a double turn, thus no technique. However if you stop and they turn, it's the same as them not turning (a single turn), and you get a shihonage.
If you want to make them pay a little more for their bad uke-ing, back out of your shihonage and stand tall as they turn, it will put lots of pressure on their arm; often making them a better uke.
The real answer is to listen to your uke, and adjust accordingly.