Hm.. if I did recommend a 'local' cutter - this would mean a rather long trip for you
However, the project sounds very exciting, so I woudl rather add the respective 0.2 than not... I have yet to see a facet map for the 'old assher'. And the name is attached to all sorts of stones. You may need to be quite specific about the proportions and look you want to end up with. otherwise, the model is not exactly among the most challenging to cut.
Is THIS it? (the drawing on the cert is not a representation of the stone but the proportions 80% depth and 49% table are, with allot left for the cutter to decide).