All 12 SPL teams agreed at a meeting yesterday change is essential, and that adding a second division would best serve their sporting and commercial interests.
The proposals are still to be finalised before a formal vote on December 3, but it is expected the agreement will be reached on two leagues of 12, with a mid-season split into three divisions of eight to contest the championship and European places, promotion and relegation, and relegation to a pyramid structure.
The SPL clubs will also draw up the criteria by which teams will be invited to join them and, while no special case will be made for Rangers, the likelihood is the Ibrox side would be considered among "the full-time clubs that invest so much in community and youth, and those who aspire to be in the top league".
The plans also counter proposals drawn up by the SFL for a 16-10-16 structure, which all 30 member clubs voted in favour of last week, but Neil Doncaster insists that there will not be an outbreak of civil war among the bodies.
"There was a unanimous view we should be looking at a new league structure which involves expansion at the top end," the SPL chief executive said. "It should be one that looks after those who are full-time professional clubs, but also those who aspire to be full-time professional clubs. Also, it should be a structure that ensures meaningful and exciting games, provides competition and works from a financial point of view.
"All [the governing bodies] exist on the same corridor at Hampden. We all want a model that works for all levels. We have to remember that the SPL already redistributes nearly 20% of its income to the lower levels. But we have to have a model that ensures that when clubs are relegated, for sporting reasons, they don't suffer financial collapse as a result.
"At the moment, there is such a wide gap between 12th and 13th position that we end up with clubs struggling to manage that gap."