From the industry based research I've carried out, you are best wearing some kind of low profile soft padded helmet rather than a hard bike helmet or standard hard hat. I would suggest maybe an old school leather hair-net style bike helmet, combined with classic marino wool jersey and three quater length fixed gear shorts from Rapha or some other fixed gear fashion retailer.
From the industry based research I've carried out, you are best wearing some kind of low profile soft padded helmet rather than a hard bike helmet or standard hard hat. I would suggest maybe an old school leather hair-net style bike helmet, combined with classic marino wool jersey and three quater length fixed gear shorts from Rapha or some other fixed gear fashion retailer.