In the past 30 years every majority government at the Federal level resulted from 25% or less of the eligible votes. To suggest that supporters of a referendum have an obligation to show that it can realistically deliver a clear consensus or that a referendum must have a specific voter turnout is complete hogwash!
I don't hear anyone complaining about majority governments who got that majority with less than a 25% consensus? Hold the referendum and which ever side gets the most votes wins, its called Democracy.
Our Constitution actually specifies that every Canadian has the right to vote directly for individual representatives of the House of Commons and legislatures. Our Constitution requires the country be divided up in Electoral Districts and that every citizen of Canada has the right to vote in an election of members of the House of Commons or of a legislative assembly and to be qualified for membership therein. So any PR voting system would violate our Constitution.