Tapering either wiggler wavelengths or wiggler magnetic fields has been used to enhance the extraction efficiency of free electron lasers. For high-extraction-efficiency systems, the electron beam dynamics and thus the system performance can depend on the method of tapering. It is shown that tapering the wiggler wavelength could yield better results for a high-extraction-efficiency system. If aperturing of the optical field by the wiggler becomes significant, a double-taper scheme is proposed that could improve results over a magnetic-field-tapered system.