Most artists on Patreon that i’ve see do this, open up a text post (not a poll) and have their patrons vote on what they want with comments so that they can keep track of who votes for what and what pledge/tier they are on. They state people in x tier get x amount of votes and it seems that having people comment keeps people mostly accurate with their vote amounts because it shows up publicly. At the same time, i know people who wont vote publicly (but will DM) because they want their votes to remain private so most artists incorporate DM’s into their voting system.
However it is far from easy or efficient so i definitely agree with this. It would be amazing to have some customization for patreon polls to setup vote amounts per tier. I certainly hope this happens at some point!