Hello Lindal Kidd.
I have the same problem as the OP, but my text is too large. You mentioned going to "Preferences/User Interface/2D Interface/UI Scaling"
I have the latest version of the Second Life viewer: Second Life Release 6.3.2.530962 (64bit), and there is no "User Interface" option when I go to me> preferences. Can you confirm that option is in your version? Thanks.