This is the same process I learned after too many years of unrealistic expectations and turning relationships tense by "change requisition clients" to death. E

This is the same process I learned after too many years of unrealistic expectations and turning relationships tense by "change requisition clients" to death. Estimate the overall project effort the best that you can, then add 20-30% for risk/scope unknowns. Then pull 30% of the total level of effort in to a small contract that covers planning, specs, UX/prototyping and perhaps a limited scope technical PoC.