My Name is wilf Millington,I am nearing completion of 5″ black five to don Youngs design..I would like to know if anyone has a drg of the top feed casing as Dons design is not quite right .Have Tried the N.R.M. but they do not have a drawing.Have the Profiles Book which refers to a drawing number C32305. but no actual sizes.Can anyone help please.The same casing would also fit a Jubilee.