To customise your overlay we need to override the default CSS code that dictates how an individual component looks, where it is positioned and how it animates etc. In iRacing Live Timing press F3 to open the Configuration Panel, scroll down to find the Style Overrides field and click the 3 dots to open the screen on the left. Copy and paste the code below into the bottom of the Style Overrides window and adjust the values to get the desired effect.
transform: perspective(1000px) translateZ(0px);
transform-origin: left top;