The fist number of L. refer to the standard CtP edition published in 1987. The following number shows correspondence between letters in the new 2010 edition. Note that on this website CtP is available only 1987 edition with minor additions.

[L. 63 | 70] 2 September 1963

I think it is extremely clever of you to have made such satisfactory arrangements for the cyclostyling of the Notes. Saturday the 7th September sounds an auspicious date, and your presence in person will no doubt ensure that the circumstances are entirely favourable. I am sorry that I too cannot be there to see the birth of the book.