Hi 'mac
Here's a refinement that lets you do a secondary alphabetic sort within the groups defined by the length sort.
Sorting individually by columns won't do this—each sort by that method is independent, and overrides the previous sort. To do a hierarchical sort, you need to use the Sort section of the Sort & Filter Inspector.

For the middle table, only one sort rule was applied:

The result is that all words are grouped in order of increasing length. Within a single length, the words remain in the same order as they were in the original list.
In the table to the right, two sorting rules were applied. The first groups the words by length; the second sorts each group into alphabetical order.

Which rule set is best in your case depends on how thorough a sort you want.
Regards,
Barry