An app that gives a user-assigned start handicap in seconds at race start, for staggered starts. Unzip into steamapps\common\assettocorsa\apps\python and enable "Start Handicap" in AC.
In a prac or qually session, use the spinner to set your handicap in seconds. Then at race start, it starts counting down after the start lights go out, and then turns into a green "GO". One second later, the app hides itself.