Last month, the SPL agreed to seek the expansion of their membership, with plans that would see two leagues of 12 split into three divisions of eight after 22 games. It is believed Monday's summit resulted in further agreement on issues such as financial distribution and voting structures.
Doncaster now hopes to meet with the Scottish Football League and the Scottish Football Association on Thursday to discuss the plans further.
Speaking after the meeting, he said: "I'm delighted to say that we have unanimous agreement in principle from the 12 SPL member clubs to the 24-18 team model.
"We are looking forward to sitting down with the Scottish Football League and the Scottish FA to talk about the details.
"What we aim to have is a consensus model that cares for all of Scottish football and that's got to be the objective going forward."