Thanks for the link. I'm surprised I didn't find when I was searching (Guess I didn't search enough). Regardless it doesn't look like I can do exactly what I want with this (Metric/Day) but it gets very close via (Day/Metric). I've marked your answer as correct, thanks.
The reason why is that you're building your workbook with Measure Names, which is an "unpivot" that lets us treat different measures as different aspects of the same dimension. For they layout you described what would be needed is one set of Measure Names (Buyers, Revenue, and Transactions) and then another set of corresponding Measure Names (Buyers % diff, Revenue % diff, Transactions %diff) for the highlight table, and Tableau only gives us one set of Measure Names per view.
My suggestion would be to do that unpivot yourself outside of Tableau, for example by using the Tableau data reshaper tool Installing the Tableau Add-In for Reshaping Data in Excel | Tableau Software or by using a custom query. I used the data reshaper on your data set, to create a Metric dimension and Value measure. Then I brought the Value into the worksheet, and used a % Difference from Prior Quick Table calculation. That gets the % difference, which I then customized and wrapped in a WINDOW_MAX() to create a % Diff for Highglight table calc that is used on the Colors Shelf, the Compute Using on the calcs is on Date so they partition on the Metric & Hour:
I used a red/grey scale because ~4% of the overall population is red-green color blind, and left the % Diff in for validation.