Writing to the audience

One of the most basic pragmatic points of writing is tailoring the language one uses to one's intended audience. I would use different words in a text book for first graders than in a paper sent to a scientific journal, even if the exact same concept was being communicated. I have to estimate the assumptions, interests, background knowledge, tolerance for jargon and a host of other parameters about my readers in order to write in the most useful voice and tone.

This becomes a problem when I don't know who my audience is. I am applying for a DAAD research grant, and while I know I need to submit four copies of my proposal, I have no information on the four people who will be reviewing it. They may be four evolutionary biologists, in which case I would like to write a fairly detailed and technical proposal, using all the appropriate terminology, so as to show that I know my topic and have detailed plans. They may be four non-biologists, but still natural scientists. They may be social-scientists, or a mix of academics from all fields. They may be (although I doubt it) four German first-graders, in which case I would write a very different proposal. But as I don't know who they are, I have been trying to write a proposal which is appropriate to all of these groups, and finding it nearly impossible. How does one write an audience-neutral grant application?