You can download Coretemp here:
Core Temp
In settings you can set it to start with windows and you can adjust settings for the logitech keyboard display. You can also set it to display temps in your task tray.
You can download Afterburner here:
MSI Afterburner
In afterburner, go to settings and when you click on each item (temp, usage, clock etc.) you can click "Show in Logitech keyboard LCD display" and choose the font size.