I think it might be smart to add a feature in to allow you to get more boss hits without gaining xp for each hit done (or maybe .5xp). However something like that shouldnt have a fee because some people may have money to pay for it but even so they might want the xp and therefore would keep buying the boss power attacks. This would allow lower hitters to catch up with boss but block them from gaining levels at the same time, and burn smaller amounts of gold with a smaller benefit than the boss power attacks.
You may be thinking that with this boss power up, people who havn't been buying gold would pay to keep up with their clans, but in reality i dont think people would want to spend 500 gold(about $40) every weekend to do so. I would also recommend adding the x2 hit power attack on top of a normal x2 attack on boss. People would spend more gold on refills since they could use it faster on boss.
Ps. Please add a refresh button on clan activity window or have it refresh each time it's opened rather than having to close out game and reopen.
Curious what there is to be said will be waiting on answer and thanks for refunding my gold with that problem I had!