It depends what account you are going to be voting for.
You get 10 100% votes a day, which is basically 1000% of voting. If you wish to keep your voting power around 90-100% at all times, which is best, I would not vote kids than 1000% a day.

For instance, if you were going to vote for my account I would reccommend 50%, since I post anywhere from 5-7 times a day. Otherwise the majority of your voting power would be dedicated to me.

If you are voting for an account that doesn’t post much, but always has high payouts I would do 100%.

Depending how popular the person’s posts are, I would vote anywhere from 15-30 minutes after they post. For instance with my account I’d say 20-25 minutes. Most of my votes come in around 30 minutes. So if you vote before then you will maximize your curation rewards.