Dorbin has put into place extreme price increases and their material has become exceptionally expense and strongly urge you to consider Reese or Pemko as alternates.
Dorbin 167B 84" Mill Brass Interlocking Threshold
In all seriousness I will happily request a 6-inch sample of each of these two have forwarded to you. Perhaps you can have the material scanned and then you can create a AutoCAD drawing from there.