The former Scottish Rugby Union chairman, is confident that his plans in partnership with Brian Simmers, the Glasgow Hawks president, will be finalised following discussions with major corporations this month.
The SRU are about to announce where Warriors will play this season, and Mackay said it is vital they continue to send the right signals to the Glasgow public, local politicians and the business community.
"Our view is that Scotstoun is the place for Glasgow rugby and, in our talks with Glasgow City Council, they have been hugely supportive," said Mackay in The Herald.
As that is at least two and probably three years from being available, he knows that the SRU have to come up with an interim plan and has sympathy with their difficulties in identifying a suitable location.
Facilities at Hughenden, their former home, are still unsuitable so Firhill remains the likeliest option for the coming season. However, West Of Scotland's Burnbrae ground has emerged as a serious option.
Gordon McKie, the SRU's chief executive, sought to make it clear that options are being kept as wide as possible, and said temporary use of Falkirk FC's new stadium could be considered.
In terms of established facilities, it probably offers a better option than any of those in the Greater Glasgow area, but Mackay is convinced that it would be a dangerous road to go down.
"I can understand the pressure of the economics, but [Glasgow Warriors] is a brand that has an opportunity to be built then strengthened," he said. "Moving [it] out of Glasgow would be the wrong message to send to the council, supporters and to sponsors."
The timing is all the more sensitive because of the negotiations in which he and Simmers are about to engage.
"We've got two big meetings in the next two-and-a-half weeks and the high probability of another two with some major players," explained Mackay. "Everything hinges on those discussions, and it has been hugely encouraging that there have been no leaks so far from those we've been sharing our information with.
"It is hard work but there has been no dampening of Brian's or my enthusiasm."
Mackay said he remained optimistic that he and his partners would be able to unveil a detailed plan for taking over the running of the pro team by September.