Thanks Bruce.
This did not provide the solution we hoped for, It only added one more character to the field.

But you got me thinking again and after playing around, I came up with the formula. Here it is:
{Item #} & Repeat(" ", 26 - Length({Item #}))

The Repeat function allows us to tell GV to repeat a string a number of times.
As you may see in the formula, I was able to get GV to calculate how many characters each Item # is, using the Length function.
Finally, we ask GV to extend a bunch of additional spaces to pad the field to 26 characters.

It works!