Yes all votes in the first 24H on a post have same CR.
Curators will get higher CR, if there is more votes after the first 24H, so you might look into post that might do this, but honestly now I don't pay to much attention to this, as the difference is small, and just follow the first two rules, vote in the first 24H and don't go bellow 80%. This for majority of the post, if I see a post I think deserve some love I don't mind if it is older than 24H. Just know these things, and then it is up to you how to act, and observe how will it impact your CR.