Unless you're HLBC, it is a complete waste to have more than the minimum necessary to reach max ally plunder. The only other exception is if you have enough free time to be ally trading all day to earn gold.
If I could go back in time, I wouldn't have bought my last 2 lands yet I would rather have 600b in allies
How can you tell what your max allie plunder value is? (I tealize this question might elicit the forum wrath but it would be good to know)
attack eb once write down ally plunder bonus then wait for regen after that buy an ally (maybe 4mil) and attack when full wirte down the ally plunder again. if they arent the same then you arent in max plunder