I've reduced the Vikings to about 6 tundra towns. I keep them alive for leader fishing, and since I'm not near the OCN for this map, I don't want to establish towns on tundra. I'm more concerned that they will raze my costal town, because they have no chance of holding it. So, I see no way around needing 3 rifles per town. Since I have 18,000g, losing a town for just one turn would cost me about 800g. That would cover a lot of unit maintenance.