WiMAX-WiFi multi-tier network has emerged as a promising solution for fast delivery of broadband wireless access services. This is particularly true in places where wired infrastructure is not ready or too expensive. The architecture also has the advantage of taking the complementary features of these diverse technologies (from technical and economic viewpoints) to provide capacity and coverage extension. However, such architecture inspires a wide range of complex and interdependent design options covering network formation, number of radio per node, ratio between WiMAX and WiFi nodes, number hops at WiFi multi-hop tier, channel bandwidth, etc. This paper provides some insights on how different possible configurations perform under different operating conditions and user requirements.