For what it's worth, the weights of my examples dies 2+A* to 2+D* are as follows: P724 2+A* 9.19g P726 2+B* 10.09g P728 2+C* 8.31g P730 2+D* 9.17g The silver ones are pro-rata with regard to density. The edge will likely be filed. Based on the evidence seen on an example of a 1729 silver proof 1/2d that went through Baldwins about 5 or 6 years ago, it seems that proofs in this period were possibly struck on a sheet and punched out slightly larger than the coin, then the edges were filed down and the excess removed. They were not obviously struck in a collar as the flans are usually slightly irregular, or if they were struck using a collar, it wasn't a very good fit. Certainly the edges aren't normally flat and perpendicular which you would expect if used and any subsequent filing would negate any finish obtained with a collar.. Clearly my 728 is at the lower end of the weight range, but the 10g or so of the 726 is about as high as I've seen or have recorded. I would suggest a figure approaching 11g to be questionable.