If you guys aren't able to find more teams soon, we may want to look at merging our leagues. Formula Harrison, currently has 9/16 members and we race on Monday, Friday, and Saturday, similar to your dates. If you are interested, PM me. Ours is only a 25% race though, and about an hour earlier than yours.
Here's the link if you want to check us out: https://igpmanager.com/play/?url=league-info/2284#tab1