In order for me to understand which build is more beneficial, I did a quick test. I have an account with 23 lands, consisting of a Hansel Build with 22 lvl4 guilds. I managed to change the attk/def building 3 times from cathedral, forge to beastiary, and recorded the following numbers. These numbers are based off an attack on a LCBC pure spy, and are recorded as the first attack after full bar regeneration with maxed ally bonus. Forge Plunder = 75,602 Ally Bonus = 10,119,717 Soldiers = 85 Catheral Plunder = 79,782 Ally Bonus = 10,128,501 Soldiers = 85 Beastiary Plunder = 77,177 Ally Bonus = 10,123,011 Soldiers = 83 Please let me know what you think? I don't have enough to make comparison in Tier3 yet.
The build has to suit you. It is probably in your best interest not to choose forge because it gives the least stats and no special bonuses. As for the rest... The bestiary's special bonus is that it allows a full unload to have 26 attacks. However, it takes longer to regen. Use this building if you crystal a lot or if you don't spend much time on KaW. The cathedral only gives a 5% bonus, but it can really add up in the end. If you're on a lot and you want to squeeze out every last bit of gold, you might want to pick this building. Hoped this helped.
so, in this case, if I were a noob, would it be better to build cathedrals than forges, seeing cath gives more gold and provides better defense?