As a longtime user of rotosound flats, there's nothing wrong with them for playing jazz - just leave them on and let them settle in.
As a longtime doubler, I agree with JimmyM. Spend time transcribing upright walking lines and playing along with recordings - especially the arrangements you're doing in school if you can find them.
The right hand has been mentioned, but don't forget the left hand. My jazz foundation is with the Simandl / Ray Brown 1-2-4 method and I can pull off an upright-ish sound/approach on just about any electric bass using those techniques.
As a longtime doubler, I agree with JimmyM. Spend time transcribing upright walking lines and playing along with recordings - especially the arrangements you're doing in school if you can find them.
The right hand has been mentioned, but don't forget the left hand. My jazz foundation is with the Simandl / Ray Brown 1-2-4 method and I can pull off an upright-ish sound/approach on just about any electric bass using those techniques.