Currently, QoSmate is primarily designed for wired WAN connections with relatively stable bandwidth. Using it with a WWAN connection might not be optimal due to the potentially variable nature of wifi connections.
However, if your wifi connection provides relatively stable and consistent bandwidth, you could give it a try. The key is to set the shaper rate to a bandwidth value that you will have available at all times. This ensures that the QoS rules remain effective even during periods of lower bandwidth.
I was considering the implementation of CAKE w/ Adaptive Bandwidth in some way. This could potentially make QoSmate more effective for variable bandwidth connections like WiFi or mobile internet.