I would add the option that all participants participate in paying the fee, at least while the fees are high. There are 50 members in the campaign, deducting $1 from each to cover the fee is acceptable, and the total amount ($50) would certainly cover the costs.
Agreed, sharing transaction fee with Sinbad and all participants to get next block addition is the way to go!
Like they say, "A problem shared is a problem solved."