I suspect there will be a stack of voting on or before 15 minutes. If you are seeking the best rewards, I think somewhere prior to 15 mins (which is the new 30 mins as far as 100% of your vote going to curation at the earliest point) will prove the 'best' time to vote.

This change could have less significance than the dust vote. Smaller accounts will need to up their vote %'s. See the post I have recently resteemed for more information :)