Amateur & Semi-pro Mangers sorely needed to fill up Rookie & Pro tiers.
https://igpmanager.com/app/p=league&id=3956&tab=info
There are no rules or limits to the number of pit-stop you make, you can do what you want, you don't have to turn up for races if the time doesn't suit you, just setup your cars and cross your fingers.
Best of all you can you can leave me for dust in the Rookie league, great practice for when you move up a tier