Does the customer have any experience with self bows? If they shoot molded grip, Olympic target bows or compounds, then they might expect it to shoot like them? They are different birds, and that to me is an unreasonable expectation.
I wouldn't touch the tiller on this bow, until you get an idea of what this guy thinks is acceptable, ie see the type of bow he shoots, how he shoots, perhaps even shoot it yourself. What weight arrows does he shoot? If they are too light that might contribute to perceived shock.
Have the customer shoot some of your other bows, and see if they find one that they like. Only then will you get a true picture whether your customers expectations are realistic.
If they are not realistic, politely and diplomatically tell them so and offer a refund. (personally I would take a non refundable deposit when you agree to make someone a bow 30-50%).
You get some people that expect the unobtainable. Even if you manage to give it too them, at a fair price then its still not good enough, and too expensive. This type of person is not worth your trouble.