Quick stats! Last year had 80 people using 1437 votes on songs that made the bracket, or a ratio of 1437/(80*25) = 71.85%. Per song, that's an average of 1437/256 = 5.6 votes, which covers the highest songs at 7/6 down to the cutoff at 4/3.
That was with 125 locks needing 6 votes each; fewer locks this year most likely means there'll be less coordination and a lower bracket ratio. We can take a lower bound of 68% on 78*25 = 5.2 average votes on the top 256, or a slight upper bound of 74% on 78*25 = 5.6. To get from average vote count to a cutoff, I don't think there's a good way to estimate it but last year can be a reference with 5.6 votes => 4/3 cutoff. I am not liable for any damages caused by this analysis!
VGMC stuff: https://p0p0p0p.github.io