I've just had another go - I realised that with slightly lower tyre wear multipliers it might be possible to use Custom Race rather than lobby for practice, provided you change the BOP of your car accordingly and don't mind chasing whatever else is on the track. I got down to a 50.1, with only one other lap in the 51s over a race distance. Everything else was 52 or more. I really can't get any consistency, and I don't know if it's the conditions or me being new to learning manual. One thing I did notice though was that I'm terrible at accelerating out of corners. The GT-R is quite sluggish at accelerating at the best of times, but I'm getting absolutely ruined here. I looked at the other GT-R and other cars in the replay and I don't see where the problem is. It's hard to be progressive on the throttle with a DS4 but I seem to be doing an especially bad job of it here.