Not even his daughter Linda Lawson, who is a director of the charity and has spent the last nine months cataloguing the archive knew the extent of his work.
"Dad spent around 40 hours preparing for each match and it was very interesting to begin the archive journey in the early 1950s when he started and seeing the way in which Dad developed his big sheets over the next 50 years to become the sought after works of art that they now are," she explained.
"Many of the later sheets contain as much as 1,000 pieces of information about teams, players and officials, etc. which were all colour coded by Dad.
"Preparation was at the heart of his success and throughout his broadcasting career he would not break from his proven routine.
"Gather information, prepare the 'sheet', learn through writing down the facts, see the teams at their practice sessions during the week before the match, speak to them in their hotel if possible armed as he invariably was with his tin of Hawick balls and then after an early evening meal on the evening before the game sit with his specially modified pack of playing cards and marry the player's name to his shirt number until the number and name were tripping off his tongue.
"This was no easy feat given some of the teams and players Dad covered from the tongue twisters of the South Sea Islanders to the teams from Eastern Europe and Asia."
Linda added: "The first hint of a big sheet was in 1956 when Ireland and Scotland played and the last was the Wales Scotland game in 2002.
"We are delighted to hand them over to the Foundation and look forward to the good that will come from the commercialisation of these sheets as part of the Foundation's charitable work.
"A small number of big sheets were released during Dad's lifetime and we estimate around £500,000 was raised for good causes, mainly cancer related.
"The archive research has identified 633 big sheets as well as handwritten notes of Dad's post-match thoughts, many of which are very interesting and amusing. There are also programmes and even copies of expenses that were submitted to the BBC.
"As part of the fundraising effort, the Foundation plans to release copies of certain big sheets for charitable events and public sale."
Foundation co-founder and former pupil of Bill's, Brian Renwick, told of his amazement at the extent of the archive.
"We all knew there would be a few but never did we imagine that there would be so many big sheets," he said.
"We, in the Foundation, are delighted to have the ability to reproduce copies of these sheets to generate funding for the Foundation, the aims of which are to support the development of rugby and its values which Bill held dear, provide sporting opportunities for young people who may not otherwise receive them and to hopefully create an education and inspirational base which will be the home of the entire archive.
"We will need to raise substantial funds to realise these objectives and there is a strong commitment from those involved.
"We do hope that clubs and the population at large will become members of the Foundation. Please visit our website for more information at www.billmclarenfoundation.co.uk.
"Bill McLaren was the 'Voice of Rugby' worldwide and while much of our efforts will be focused on Scotland, the intention is to progressively expand our charitable work throughout those countries that have bonds with Scotland and with Bill McLaren.
"Bill commentated on so many matches from all over the world and we know that there will be thousands of players, officials, families and clubs who would like to have a copy of a big sheet and so many youngsters that could benefit from sharing the life values that Bill, as a PE teacher, instilled in the youngsters of Hawick.
"There are so many memorable matches such as the inaugural rugby World Cup final in 1987 which New Zealand won, Grand Slams, Triple Crowns, Heineken Cup finals, club matches, Seven-a-side tournaments, first caps, last caps - the list just goes on and on!
"Bill stood for everything that is good in sport and we need to remind ourselves and others of the need to maintain his high standards."
For more information on how the Bill McLaren Foundation intends to use these big sheets, please contact firstname.lastname@example.org.