1. Attrition: each time you fight or negotiate for a sector does your attrition increase. It makes each bit of progress more and more difficult, but it also resets every 24h. This forces players to manage their military units as well as goods on a daily basis and not to spend too many of these, and, to time their use to when they're needed the most and to save some when your guild is in the lead for example. But burn through too fast during the first days and you may have exhausted yourself at the end of the 11 days. Finding the right strategy in managing your attrition will play an important role to your success in GBG. You'll find your current level of attrition in the top left corner. Here is a picture of an attrition of 1 after a single fight:
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So in the next fight do I have to fight units with a 2% attack and defense bonus, while negtiations will still only cost me 1 good each turn.
2. As said above can one fight or negotiate to advance on a sector. Your personal goods are used for the negotiations. Guild treasury goods are only needed for placing buildings such as banners and outposts after a sector has been taken. It's not necessary to place a building on each sector, but as each building gives advantages can one spend guild treasury goods here to gain over the competition - or to make their life harder. These buildings can however be quite costly and deplete a guild's treasury quickly. If your guild often has to struggle to unlock GE levels for example, because you frequently lack the goods, then you should be vary careful here. Hence it also has a special right that your guild leadership can assign to members before they can place buildings in GBG.
3. There are currently no special GBs dedicated to GBG. However, many of the existing ones do find a good use. So do the attack and defense bonuses from Zeus help in the fights (if you choose to fight), the goods coming from a Tower of Babel help with negotiations and an Observatory helps with producing goods for your guild treasury, just to name three GBs here.
4. The Statue of Honour at it's highest level gives you 6FPs when motivated and a good chunk of coins, too. That's not too bad for a 3x4 building. It also gives guild power and donates goods to your guild treasury, which makes it useful for GBG, GvG and as well as for unlocking of GE levels. When you do 2 out of the 3 regularly then you probably want one. Here is a picture of it's stats for the Late Middle Ages:
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