I went into my monitor settings and changed the DPI from my default 90 to the other setting of 120 DPI ...
I get the same larger font as your OP ...
I think your issue is in the monitor settings and not a Humviewer issue ...
In Vista ... (I'm not sure in Windows 7)...
Right click on the desktop ...
Select "Personalize" ...
Select "Adjust font size (DPI)" ... (In the left column) ...
Change to a smaller DPI scale ...
But this will make all your font smaller ... Not just Humviewer ...
Rickie