I'm with you- box cake mix all the way! I used to use boxed brownie mix too but my daughter loves to make brownies from scratch so now I just don't make them at all.
Your cake sounds like it will be perfect!
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"If you have men who will exclude any of God’s creatures from the shelter of compassion and pity, you will have men who will deal likewise with their fellow men." — St. Francis of Assisi, 1181-1226