Default value is 3 slot counts for auto save. You can do it in menu Maximum Auto-Save slot Number. If you want, you can limit count of Auto Saves, that are will be rotated every Auto Save.
For example, if you entered value 2 in menu Set period between auto-saves and selected Sim Hour in menu Period between auto-save is counted in, Auto Save will be triggered every 2 Sim Hours :)! Default value is: Sim Hour. Functional of the mod (description updated up to 39.0 version):
