Referring to the clock that counts the time since the last nuclear test:
I want to make today the last day where I change the figure on the clock.
I'm confused by the particle で in this sentence. Maybe I've mistranslated, but I would have expected it to be 今日を. I'm thinking of the pattern AをBと/にする meaning "make A as/into B".
Depending on the explanation there's also a possibility I'll be confused as to why it's で and not に, but at the moment I don't see how either one works.