I've been running a group since August. Our first session we played out the Assembly as a high-level meta game as per the book's initial concept. However, this proved to be an exercise in mechanics (players picked projects based on their skills), was rather boring in so much as there was no role playing, provided little to the actual game, and never made sense as to how 'low level' PCs were running the show. It lacked conflict!
Leaving that session I realized a change was needed. I have a large group (7 players) and developed 8 NPCs -- The Elder (I play) and 7 leaders (4 Bosses, 2 Chroniclers, and 1 Slave*). Each leader came from the initial PC character / Ark development so had relevance to the players decisions. I fleshed each out further with a short Bio (no Stats) and let the Players decide which they wanted to play at the new Assembly. I also created a set of goals each NPC had for Player to complete, where the PC got +1 XP per goal completed. The Slave leader was special 'wild-card' as he only voted when breaking ties and 'usually' did so for the owning Boss (also a leader) - his Player's goals are often centered around either gaining freedom (via a vote) or setting up votes that ultimately sewed chaos.
Each time the Assembly comes together I hand out a set of new goals for each NPC leader (~2-3 each) that are invariably opposing the other NPC goals, and then... let the Players go. The Assembly has turned into a 'Game of Thrones' style event where alliances come and go. For example, the session where the PC's decided to send out an expedition for the first time, three of the leaders had their own separate goal of having a different PC leading the expedition -- only one Player could score the +1 XP and so created some of the fiercest ('best') role playing seen as each jockeyed with the other four players for the votes needed...
The change is awesome!!! Basically the players get two separate but connected role playing events in one night (we play ~4-5 hrs in total and I try to keep the Assembly running no longer than 30-45 min of that time).
Also, I think having a chance for players to complete directly opposing each other with (almost) throw-away characters, ultimately brings the group together when role playing the PC group as the group dynamics are really tight and friendly.
Mind you, it is a fair amount of extra work for me to prep each session, but in doing so I get the chance to craft a wonderful story with 14 remember-able & fleshed out characters (7 NPC + 7 PC).
... now to plan the Elder's death and the power-struggle that ensues!
Note: each leader is stat-less - which was intentional so as to allow the Player to play the NPC they way they wanted. After each Assembly, when the Players role for the various projects they still use their respective PC skills since they would be the actual workers...