Costway Dumb Trainer settings

I have just started with zwift and found a second hand trainer. The guy told me it was a Costway Indoor Trainer - magnetic i think (

This is obviously not supported by the Zwift team but I wanted to set it up as realistically as possible. The settings go from 1 to 8 with 1 being the hardest.

What would you all suggest as a setting for the trainer?

At the moment I have set it at 6-7, which feels about right.