Revisionist version 1.5, which makes it easy to manage and preserve saved versions of your documents, is now available for El Capitan to Catalina. This contains significant improvements in its interface, which now allows you to size text in all three of its window types, anywhere between 4 and 24 points. In the main window, this applies only to the lower text view. This version also improves saving of window position and size.
There is currently one remaining issue with the latest Catalina beta: that fails to return the size of the hidden version database at the root of the startup volume, as the new read-only system volume uses a different location at present. I intend correcting that in a further update nearer the final release of Catalina, when such locations are more stable.
Revisionist 1.5 is now available from here: revisionist15
from Downloads above, from its Product Page, and through the self-update mechanism in previous versions.