Since you got 10 packs, the best way is to rotate between the top 20 or 30 bp members in your GNW participants for alternating weeks. IMO these is to secure the presence of your top members. Only those critical and present to GNW should get packs as that is the only way to secure packs. From what I understand, there was a previously big and strong group in our server who split into smaller groups just because it is inefficient to get packs when the group becomes too big. There are also members who would leave if they felt they deserve to get more packs or more regularly, which is quite disappointing when that member could be a core strong for GNW.