Based on an ongoing discussion on Ares global, I took a look at the available information for the anniversary event. As usual, fairly comprehensive tables were available through the European wiki, including the amounts of balloons needed for the individual quests, the amount needed for the general server goal, and the conversion rate for resources to balloons. Much of the conversation included increasing water production, as was needed in the last anniversary event. However, looking at my stored resources, it was clear that water would not allow me to complete the event. This encouraged me to look more closely at the balloons that could be obtained from resources.
In the first iteration, I simply compared the number of resources required for each level for some of the products. The products were selected for what resources were more likely to be donated, although ultimately it does not matter. The results are shown below:
In the second iteration, I normalized the number of resources required to get balloons. The numbers are rounded visually, although the entire number is stored. From the information shown, between 30 and 40, the value of water substantially drops, making it the worst of the listed resources. Before level 40, the resources best ratio to worst are: marble > sausage, horses > water, HWP > wheat > brew > bread. After level 40 (including the final group of resources), the ratios change to: saddle cloth > wool cloth > EWP > marble > sausage > horse > HWP > wheat > brew > bread > water.
Finally, the increase in the amounts was calculated based on the normalized resource ratios. From there, it is obvious that a fixed ratio to determine the increase of resources required against level. Water seems to have been singled out with a 10x normal increase going from levels 30 to 40. Otherwise, the number of resources increase as shown, with the largest normal increase going from levels 40 to 50.
The missing variable is the time required to convert the resources. Otherwise, balloons can be produced at a lower cost by lower level players. This would only be of value once the individual player has completed their personal goal for the event. The real question is if there are enough active people on the servers that it will be possible for us to donate sufficient balloons.