I have done some reference work on this coin and figured there arr three varieties of this 1911 Chinese dollar, the first was struck with a blurry die, the second and rarest is a clean strike with an extra spine on the tail on top of the smoke, and the third was a later strike with a dot after the word Dollar.
If you look close at the R on mine, you will see it is a P with a leg added. This is correct for the first and second strikes.
the weights and dimensions are atandardized on all three variieties
By the way, mine is the second strike, as can be seen by the spine on top of the smoke at the end of the tail.