I love your proposal but the Old Firm (and TV) want 4 matches per year.
You could have a 14-team league, play each other 3 times (39 games) and have a local derby as the 40th game giving the Old Firm their 4 matches and then you can have St. Mirren-Kilmarnock, Hamilton-Motherwell, Hibs-Hearts etc. I'm not sure about a split (I don't know why we need a split) but I think a 14-team arrangement needs to be permanent and not 2 years or 5 years.
I'm indifferent about leagues below the Premier, but perhaps 12 in the Championship and 12 in League One? I think 40 teams now is too many.
The Rangers proposal is pure self-interest and I hope we vote it down.