Couple of points- the Dax setup may be great and superior to Grubee, I have not compared, but my understanding is that it uses a centrifugal clutch...just like the Grubee- I do not see a difference in the operation in that regard.
I think Staton also uses a centrifugal clutch. This is "automatic" in that all you have to do is rev it and go- but the same is the case with a Grubee with the engager...engaged- You don't just take off when the Grubee is engaged, you still have to rev it for the clutch to engage. If I am mistaken about the Staton and Dax, I desire to be enlightened. I most definitely am not mistaken about the Grubee- it's parked in my garage.
Next- here's the thing- the concept of a "clone"- the Huasheng engines available for the Grubee are "clones" of the Honda GXH50- that means that, externally at least, they are supposed to be identical to the Honda (which came first). Internally and metalurgically, I don't know how identical they are.
However, what I can tell you is this- the muffler that fits the Huasheng "clone" of the Honda- will fit the Honda. How do I know? Again, see the pic I posted above. People have looked at all these issues before and the discussions are here for the searching. believe it or not, there are people here with significant, personal experience with the Honda GXH50 and Grubee setup.