In a text editor like Notepad, open the file
Make the JavaOptions section look something like this, (especially -Xmx8G and -Dsun.java2d.uiScale lines at the bottom):


Adjust the "java-options=-Dsun.java2d.uiScale=1.4" to your liking.

Close and reopen JWildfire every time you edit the file.


Here's what JWildfire looks like with uiScale=2.0 (HUGE!):




I found 1.4 was about how I like it, but feel free to experiment. Good luck!