I know this is very late to the party
, but I wanted to comment as someone in this situation.
100% of the proceeds for my book are being donated to charity. Well, to be exact, 100% ebook and 100% print, minus production costs. I'm pubbed through a small press. Upon signing my contract, I asked my pub if it's okay to donate all of my share. Of course she said "sure" because, well, it's my money
My pub then pledged the company's share. Since ebooks cost next to nothing to produce, she was fine giving that money. The print she cannot donate all of hers because of production costs. But the royalties she donated.
How it works is she trusts me, mostly because my charity is my nephew's cancer hospital, to make sure the money goes where it's supposed to. 1st of every month, she cuts me a check. I'm waiting for quarterly sales to hand a lump some over to the hospital, only because the person in charge at the hospital is very busy and I don't want to bother them all of the time
I have talked with the hospital manager (?) and she is fine with me advertising proceeds going there. But keep in mind, I wrote a picture book and this is a kid's hospital. If there is a conflict of interest, say I wrote erotica or a novel about a pedophile, they may have felt differently.
Any other question just PM me.