The shape of the wood covers I have bought from China that look like yours reduces the space between the reed plate and the covers. I find that this reduces the resonance of the instrument and affects how reeds respond to a sharp attack. Oritta make wooden covers that are shaped more like Sirius covers and have a much more open sound. In saying that, the difference in sound between regular and wood covers is heard more by the player that the listener.
The shape of the wood covers I have bought from China that look like yours reduces the space between the reed plate and the covers. I find that this reduces the resonance of the instrument and affects how reeds respond to a sharp attack. Oritta make wooden covers that are shaped more like Sirius covers and have a much more open sound. In saying that, the difference in sound between regular and wood covers is heard more by the player that the listener.