Got it to work! As you indicated, in my beastmode calculated field, I had to first aggregate my number, then wrap that in a CONCAT() function. The resulting calculated field then showed up in the list to choose from for a Summary Number, even though it's a "Dimension". Thank you!

Excellent, thanks!

DataJake - Thanks for the Bullet Graph suggestion. That might also work nicely for me, I will look into them.

That looks like a great solution to my issue, Godiepi (thanks!), but I can only see Measures, not Dimensions, in the "Field & Function" list when configuring the Summary Number, and the only beastmodes Measures that show up are ones that have aggregation functions (such as AVG). Is there some trick to getting the beastmode…