So... rough calc...
Lets say, HIVE is 0.5$, and lets assume a 10% APR (quite easy to achieve for big amounts of HIVE power, and this would be including some of the APR that comes from the inflation, driven from the compounded voting), then for 3 months... we have:
3$ is 6 HIVE, so, for this to be gained at 10% APR in 3 months, we need around 2400 HIVE power delegation, for 3 months. Although, in this case you would need to consider this as a model that can "undelegate" at any time, but if the rate of HIVE is maintained, then the 2.4k HIVE constant delegation will be sufficient to maintain the payment.
Note: This might not be the best way to do business because with HIVE power one is also giving away other values... such as voting rights, etc... so, I would make a bigger case for the APR (meaning, I would consider it more valuable than just 10% APR). And I would ally the used delegation to some useful way of helping HIVE. Such as promoting posts about the game for example... you get the idea.
Just brainstorming.