Dead on. I used to this model to edit student and colleagues' work for years. Impt to note is that it's a huge time investment to give feedback for the 30% part. I want to know from the start what the person wants, so that I don't invest time and energy into a project when he or she really just wants a copy edit. This model is a win-win for both sides.
At first, I was concerned that folks would rather wait to give until they'd "made it beg" or were old. Survey results showed "waiting" as the least impt reason for people not giving to charity. Really reinforced the idea that people just need to have a more straightforward way to connect right now with causes they will love.
One of our top metics involves examining how charities evaluate their progress. To what extent are they reaching their goals? Are they iterating as a response to their evaluations? Omakase works with nonprofits that make their program and organization evaluations public.
We're working to provide a simpler, faster experience, focusing on connecting tech folks to small, innovative charities that meet our rigorous standards (you can read about them on our website). We want to make the experience feel small and more precise. We'd love to hear more suggestions on how to do this better.