I like to make sure to upvote at least 1 full cent on the display. So for me that is 4% today, but typically go with 5% just because it's a round number. But if someone clearly took time on a comment it can be worth much more.
For posts I have been trying to give at least 3 cents, but 4 cents is better. But really depends on my voting power. 3 cents is 15% and 4 is 20%.
But when my voting power was lower I always tried to make sure to upvote with 1 cent each time as a minimum. It's just nice seeing that show up IMO.
Not bad
20% is 0.01 and 25% is 0.02
25% eats up my VP to quick
You can play with the slider bar here:
https://steemworld.org/@wolfhart
Looks like you could go all the way down to 8% for a 1 cent upvote so I'd use 9%. and 22% gets you 2 cents or I'd go with 23%.
Those couple percent add up over hundreds of votes in a week.