So the bigger the transaction the more votes. But if sending transactions to yourself count, isn't that a possible abuse? I'm sure you though of that one already though..
More questions: What exactly does the trust level do then? And what do the different levels correspond to?
When you transfer funds, it un-votes whoever the funds voted for in the last deposit and votes for the new guy. So sending to yourself just slowly removes votes as you keep paying some to fees =). So at any given moment, 100% of the stake is voting for or against a delegate.
Trust level is just local to wallet, it is used by the wallet to figure out who to vote for. It will attempt to pull votes off of untrusted, downvoted untrusted, upvote inactive trusted with most votes, and upvote active with least votes, in that order.