The preinstalled Microsoft fonts works just fine
That is because they are "system fonts"
The only way I have found to change Fences font and size is if the WindowBlind you are using has the changes done in SKS that are required for this. Has to be done using skinstudio in the font section. From my Screen shot you can see I changed it in these locations. Explorer/ Windows Explorer. Fences. Photoshop menu. These are all controlled by a System font. Changes take place in Win7/8 10.
Without doing the above the only thing I can see is changing the "Lable font" If one wants to see what it says under the icons on the Fence they are System Fonts and not changed in Fences Config.