If you feel one of the two is clearly more likely to win, even if you aren't too sure, vote false.
If you think it's basically a tossup vote true.
This poll could easily be criticized, but I don't think it clear at all as to which candidate will win, so I vote true.
It could remain close up to election day and even longer.
Edit: I screwed up the other poll, so I re-did it.
Part of this depends on context.
If one wants to color a map which some states shown in yellow…Election 2024 is a “Tossup”.
If one wants to figure out which of these two major U.S. political parties is likely to win with each level of U.S. President, U.S. Senate, and U.S. House…to conclude Election 2024 is a “Tossup” is not realistic.