Iva arranged several Nexuiz compos at small lans now and this is how we did it, if you wan t some input.
We played DM open for all, in heats, max 8 players each heat. The best from each heta made it to a finale with 4-8 players.
We played max 10 frags max 5 minutes each map. All maps (dm_nexdmNN) and the total number of kills overall won the heat. Then the one woth most kills in the finale won that one
We used the scorelogging and then figured the result with my score logs parser found at
http://excalibur.nvg.ntnu.no/nexuiz/statsparser/ to figure out who won. We warmed up each heat and the finale with the dm_nexdmextraNN maps.
With 1.5 I'd consider playing the finale LMS (last Man Standing)