Best way to compare the same month across four accounts side by side

Two answers, one for the mechanics and one for the thing you actually asked at the end. Mechanics: the filter at the top of the optimization and analysis pages takes more than one account, so you can select all four and see them together rather than opening each in turn. The account column tells you which row belongs to where, and it sorts, so a single view answers most of what you are currently assembling by hand. The harder half is your second point, and no tool solves it for you: comparing four accounts of different sizes on absolute numbers mostly measures size. Ratios are what you want - cost per conversion, conversion rate, the share of spend going to terms that never convert. Those are comparable across regions in a way that spend and click counts are not. The one absolute number worth comparing directly is wasted spend, because a region wasting £900 is wasting £900 regardless of how big it is. That's usually the row that starts the useful conversation.

Multi-account selection does most of it. The ratio point is fair - I have been presenting the regions on absolute numbers for two years and the biggest one always looks worst because it is the biggest one.