Doesn't really matter on the percentage unless you have a bunch of Steem / CTP Power....If I find a post that I really enjoy, I give them a 100% vote. Most of my curation on CTP is at 50%....But for comments, I do around 15-20% upvote.
Depends though on how much your vote is worth.
Interesting, I've got a few days before my votes are worth anything. I like clean numbers, maybe 50 curation - 25 comments? Just tossing it around before I go live. Since I have you, I have steempress set but that's obviously going to bypass ctptalk. Stupid question?