Currently, the magazine layout option overrides the presentation page columns per post. That is, if I enable Post Excerpts | Magazine Layout, the presentation page shows two posts per column, even if I set Presentation Page | Posts Per Row to 1.
I’d prefer the opposite behaviour – Magazine layout means 2 columns except the presentation page, which is set by the Posts per row field. Actually, even better would be for a sticky post to have a full column, and for others to be in two columns.