Have you tried looking at the Tekno site for driver setups that might have some of the track conditions you run in... I ran Bornhorst's McColloughs setup and worked well at many tracks and felt planted.
Also don't make a lot of changes at once, cause then you wont know what really fixed it, of helped it or made it worse... make a couple small changes and run some laps, determine if that helped or not and mark down the changes as you go.