Each upvote uses 100% weight, you earn credits based on your current voting power and your total steem power, to make it fair.
Only posts submitted from other steemvotes members are upvoted. Upvotes are made as long as auto liking is enabled, or as long as there are posts from other users to upvote, or until you run out of voting power (in that case your account is set to sleep for 3 days to recover).

I hope I could answer your questions.
I just registered on steemchat a few minutes ago. Maybe it takes some time :)