I've got 320km on my pre-aged B17. One thing I've noticed is that unlike my stock saddle, "close enough" doesn't cut it for positioning. I noticed that I was sliding forward a bit, so today I raised the nose about 1mm or less and it made a huge difference in comfort. It takes a while to find the position that is just right. Unfortunately I think that position might be slightly different for the two pairs of cycling shorts I have (different thickness of chamois).