Best time to send abandoned cart email by Dudley

I was wondering if there is any research (or what you have observed) on when to send the abandoned cart email. We currently use "Abandoned Aid" app which sends it one hour after abandonment. The built-in functionality gives you an option of delay either 6hrs or 24hrs.

What is your experience? Also, which abandoned cart email do you use and how is it better than the one that Shopify provides?

Thanks, Dudley