There are other scripts that can help you with leeches. You may try them and find out which works best for you.
One is Leech training. This setup quizzes specifically targeted to leeches. It keeps track of which leeches have been learned so they don’t come up again in subsequent quizzes.
You may also consider Item Inspector. (Disclosure: I am the author of Item Inspector) This script displays the leeches in a table on the dashboard. You go over them one by one. reciting meaning and reading. Then you hover the mouse over the item and the answer is displayed. If you click on an item the item page is displayed.