Thanks for sharing this — I don’t have specific answers to your questions, but your proposed model raises a few additional questions and considerations that might be useful as you refine the approach.
I would think an hourly. monthly, or per grant program fee structure would make more sense then a %… your costs are going to be largely “fixed” and the amount awarded wont really change how much work you are doing.
If it does not already exist - I would suggest thinking through a conflict of interest policy around this work - particularly if any recommended grantees are fiscally sponsored projects within your own organization.
I’m having a hard time envisioning who the actual contracting parties would be for this arrangement. The DAF sponsor, the donor advisor, someone else?
I know DAFs have certain restrictions on what qualifies as an appropriate distribution. A DAF can have certain administrative costs to the Sponsoring Org but paying an outside “vendor” for services to advise the DAF on grantmaking may bring up some issues.
Sorry this asks more questions then provides answers… but hopefully this helps you move forward in some way with structing the costs appropriately!