I hope this fulfills your requirements.
After a string of Google searches I discovered this PDF after searching "London Conference in 1953":
Page 4, section 1.2 states that the conference incorporated a collective 29.7 billion Deutche Marks, that of pre- and post-war debts. I did not compensate for inflation in light of the aforementioned point of contention.
On page 5, section 1.4, the specifics of the agreement are stated. They are as follows:
- Pre- and post-war debts were each reduced by about half
- Pre-war debts were reduced from 13.5 billion to 7.3 billion Deutche Mark (or 46%)
- "Post-war debts that had been negotiated prior to London were reduced from 16.2 billion to slightly less than 7 billion Deutche Mark" (or 51.5%)
- A reduction of interest left 2.5 billion interest-free, whereas 5.5 billion had an interest rate of 2.5%. The remaining 6.3 billion had an interest rate of between 4.5% and 5%.
- A five year grace period had been agreed upon and lasted from 1953 to 1957.
- ".. annual amounts of 567.2 million Deutsche Mark had to be paid" during the grace period
- Creditors had to decide whether to receive principle or interest throughout the grace period, but couldn't overstep the predetermined "fixed ceiling".
- "From 1958, fixed repayment and interest rates of 765 million Deutsche Mark were to be made."
- "Interest arrears were reduced by one-third and capitalised; current interest rates were reduced by one-quarter and were locked into the 4 per cent to 5 per cent range."
From what I can tell, the remainder of the document discusses how other countries fared when in similar situations, and how Germany managed such an economic feat. It also touches base (I think) on the current economic crisis currently inhibiting Greece.