QTR-Quadtone RIP

I am having a bit of difficulty using the standard step wedges available in QTR, as the steps are just a bit small for my Spyder3print.  I'm not sure if it isn't sometimes being affected by the sensor going outside the step.  It's also a bit of a faff trying to align the sensor.  (Currently I'm doing it on my chest with the step print resting on a copy of Steam Steel and Stars, O Winston Link, thoroughly recommended for scanning tests and looking at!).

I had been expanding the strips, when printing, but wonder if this effects the values of the steps, I'm aware ink separation.tif should not be expanded.  Also I need to keep away from the ends of the print as micro-banding will affect the steps at the end.

Would I be able to crop the step wedge tiffs in half, "double deck" them and then expand them in Elements without compromising the tonal values?
Is there are larger step wedge available than the ones I've found?

Ross