In simple xml there isn't a setting for panel height in a <single> type panel. The height is adjusted based on whether you have added a label "under" the value or not. That's where the jagged bottom edge comes from.
However, you can use row grouping to smooth that out.
documented here if you have say, three single value panels across in a row you could adjust the row tag so it looks like this:<row grouping="3"> that will put the three single panels in one solid horizontal stripe across the length of the dashboard. if you only wanted the first two together and the last one by itself you would say: <row grouping="2,3">
With Splunk... the answer is always "YES!". It just might require more regex than you're prepared for!
