You were correct.
I tried your code but it didn't do anything. I searched and found an old thread Troubleshooting TPIC6B595N that had code I loaded and now can verify that all segments light up (it lights everything and then turns off and repeats). To know I have a working display is fantastic news, but I am still only at the beginning of learning how to make this function as a simple countdown timer.
I am still looking for any links to tutorials or reading material on using shift registers that might help me along the way.
Thanks for your spot on advice so far.