I don`t know about it being a great thing as you probably don`t have the pedigree of the glass. I`d grind it and get a polish on it and see what happens. If it seems good then finish it out to a nice parabola or whatever you`re going to make of it - another dob is almost a bore to me anymore. I`d love to see a large Stevick-Paul scope as it would be a wonderful photography scope. A pair of spherical mirrors of about 60% of the primary is what the other two mirrors are going to be - the mirror and it`s glass tool both polished up.