I think auto-voting should be 1 order of magnitude less than manual voting. At least and to begin with, enforced by the code.
Auto-voting can be very beneficial indeed... but because abusers just don't care... it makes the platform really painful to explore.
In a more advanced scheme, voting reward curve should be dependent on an score based evaluation, independent of rewards. This scoring average should impact both sides... user giving the score and user receiving the score.
Then over time these "scorings" will shape and show who is "bad" or "good" in giving good scores. That associated with the rewards pool, automatically can reward the post according to the power of the user.
Using this method, the user does not need to understand by default how much money he/she wishes to give from his power. It should be allowed to be tweaked if wanted (per cap basis) but eventually per general population of the blockchain, this would probably solve the "problematic" about big whales and "automatic" non necessary human, curation.