Hi, thanks for your question.
Your credit is 15% of the first $200 of the donations and gifts you claim, and 29% of the balance. It may be more beneficial for you not to claim them this year, but to carry them forward and claim them in one of the next five years.
Because the tax credit on the first $200 is at a lower rate, you should claim donations of both spouses on one tax return. This way, you incur the lower tax credit rate on the first $200 only once. You can claim donations that your spouse made as long as your spouse does not claim them.
The optimizer can be overridden, here's more info: https://turbotax.community.intuit.ca/questions/1189896-how-do-i-override-turbotax-s-donation-optimiz...