Despite the length increase of tag names to 35 characters, there are still titles that exceed this limit. Case in point: National Lampoon's Christmas Vacation. Strip the apostrophe and replace the spaces with dashes, and you end up with a 36 character tag.
In this case I've decided to remove the "s" as well, so now it's https://movies.stackexchange.com/questions/tagged/national-lampoon-christmas-vacation .
Was this the best approach?