Nick @ngerakines.me has implemented code for the permissioned data spec, and has been walking through different app approaches. Check this write up on polls and look back at his previous write ups - from personal bookmarks to forums.
Nick GerakinesFifth shape in the atproto permissioned data series: polls. The member list is the electorate, your PDS holds only your own ballot, a vote's record key mirrors the poll's, and a leaked ballot proves nothing because permissioned commits are deniable.