I seem to remember John telling me about when he and Burton supplied blanks to George, he was cutting them off. I believe at that point they started supplying him with what John referred to as "shorties", still full splice blanks but with a much shorter backend. Maybe shortly after that he started buying even shorter blanks from Gus.
Not sure about rosewood blanks but I know they supplied the ebony blanks shorter
John has also told me he made short and full splice blanks for George.