Also wanted to mention – if you implement the above solution, the “Source URL” clickable label link will still be handled incorrectly, like so:
/Ultraspecials+Systems.html
…but that’s fine – if you visit the actual URL (/Ultraspecial%20Systems.html) it will successfully redirect you to the new page. You just can’t click on it from the Redirection rule, which is a perfectly fine trade-off to me since the redirects are working!