Mr Gray yesterday met Sir Peter Housden, the Permanent Secretary of the Scottish Government at Holyrood, to discuss Labour's plans for government.
The Labour leader said the meeting was "very productive" and he confirmed that his shadow cabinet would open discussions with top civil servants about "how we would implement our policies".
The Scotsman has learned that the series of meetings will start within three weeks on how a newly-elected Labour government at Holyrood would implement a national care service and other key party policies such as single police and fire services, as well as a cut in the 22 health boards.
Mr Gray's initial round of talks yesterday came after he announced a raft of uncosted new policies at Labour's conference in Oban, which also included a 40 million plan to create jobs for unemployed teenagers and teacher recruitment drive.
He said: "It is vitally important to be honest with the public and offer them a credible approach to government that entails taking tough decisions.
"The meeting I had with Sir Peter Housden was very productive. I will now ensure my shadow cabinet open discussions with civil servants over how we would implement our policies."
A spokesman for Mr Gray said: "We will now develop our plans for a national care service to meet the challenges of care for our growing elderly population in the 21st century just as the NHS met the health challenges for the post-war era.
"We also focus on our programme for an apprenticeship guarantee for all 16-18-year-olds as well as reform and efficiencies in police, fire and rescue and health boards."