To change the size (re-size)the desktop clock please restart the aero desktop clock. And use the slider to re-size the aero desktop clock window.
Move to the left to make the clock smaller or to the right to make the desktop clock bigger (... see Image-1 Arrow-1) !
Please use the latest version of the aero clock: ... TheAeroClock
FAQ 3: Updated on: March 26th 2014 22:05