Have you asked what they've paid in the past for similar licensing campaigns? That will give you a better idea than simply "we have a tight budget."
Also, I understand you don't want to stress your relationship with the insider but you can't worry about him. Certainly be considerate of the situation, and be diplomatic, but this is business and you can properly act like a businessman looking out for his interests.
I recently sold a one-time one-use license for one of my images to be used in a storefront. They're paying a lab to enlarge it to about 92" x 108" to be used as a "windowscape" in a shopping center. I directly asked my contact person, on the telephone, what their budget was. She said they had not done anything specifically like this before, and did not know. She then suggested a range of amounts they'd paid for prior projects. I took this info back to a friend of mine who is a commercial photographer and we picked a figure in the middle. We both felt it would be a fair rate, it was already one of my stock images, and I wanted to be seen as somebody with whom it is easy to do business, without giving the store away. I'm hoping for future work of course, but they never suggested any such thing.