Is it counter productive to ask a custom frame builder to build around a certain pre-fab fork?

For example, say I am itching for a steel race frame to be built on an Edge 2.0with a 11 to 13 cm stem (what ever the builder says is works better).

Given that all Edge forks have a 43mm rake, am I creating a significant obstical to myself and the builder to create the best fiting and performing bike possible by imposing this limitation--as opposed to letting the builder fabricate a fork to whatever length he/she feels is best.