The reservoirs are not the problem. I had one leak completely dry and the brakes
still worked fine because the fluid in the line leading from the MC, which has a tiny reservoir of its own, was sufficient to keep air out of the system. They are prone to leaks though.
Classical Gas -- have you reviewed the installation instructions found here:
http://www.erareplicas.com/427man/br...conversion.pdf paying particular attention to the .060" centering requirement, shimming, and caliper bleeding eccentricities?