I'd like to try and work out with this specific shihonage for the perspective. It is frustrating that I can't, I can't really speculate beyond that I prefer different ukemi. Without actually applying the technique, it makes things hard to speculate.
Next time you're in the Boston area, come visit the Goshinkan in Newton. You are welcome anytime.
Or drop by any Yoshinkan dojo in your area. The shihonage pin is one of our basic techniques (kihon waza) so you should find a uniform approach to its execution at any Yoshinkan dojo.