"should donate...". In the sentence, "donate" lost its meaning of a voluntary action and got replaced by a duty, an obligation.
The resolution should state that at the conclusion of each assembly, funds in excess of the target balance will be donated to the worldwide work."
In the context "resolution" indicates that a proposal is submitted to a vote, but immediately, when you add "should" and "will be", it loses its correct meaning and becomes an order from outside of the committee. What's the point of forming committees and casting votes. These guys are shamelessly out of Orwell's Nineteen Eighty Four