Albert, I tried middle hole (10*) on my duo a fortnight ago , and it went well.
Not sure if it was faster than zero though, as the track hasn't been as grippy lately (with my worn tyres.lol).
I ran regular 11.8 -9s. That was cruising too. Trying to keep it clean, as everyone else hacked each other on turn two.
Also, try a new pack ,as voltage sag makes a big difference.
Cheers,
Fleety.