Question about Sirui MP-20 Quick change base

The existing quick-release base does not seem to be removable. You can screw the Sirui MP-20 onto the quick release plate of the Joby, but this is not optimal in terms of stability and you then need an Arca Swiss compatible plate to mount the camera. The plate sizes of the two systems are different; Joby uses the Manfrotto standard and Sirui uses Arca Swiss as mentioned.