I just had a couple of quick races with Karsten. The draft was set to 'weak'.
In race 1, Karsten hung onto my slipstream well, although he wasn't quick enough to overtake, so I had the edge on him.
In race 2, we kept the draft on weak, but I applied the maximum success penalty -30bhp. Karsten led for most of the race (until he made a mistake), I was keeping up with him in the draft although I wasn't able to make an overtake on him. I just didn't have enough power down the straights, so I can't overtake in the braking zone and my best opportunity to overtake is on corner exits or to apply pressure and wait for a mistake.
We didn't try draft on 'real' but from what I just exprienced, I think that overtaking will be pretty much impossible for someone on the maximum success penalty and they would really struggle to keep in the draft at all.
It was difficult enough trying to keep up with Karsten on the weak setting.
Solo laps, I can do a low 1:29 with full power, in Karstens draft with -30hp I did a mid 1:29.
If we do change to using 'real' I think that we'll need to alter the success penalty too, it will be too much of a disadvantage.....and I like a challenge.
Looking forward to testing this in a full blown race.