I lived in Normy for 25 years and can confirm that fans of Cas and Wakey tended to be fairly evenly split.
I found when I was out drinking that you tended to get them congregating at their respective ends of the town. When all the pubs and clubs were open, you'd tend to get mainly Cas fans in the Hopetown WMC, Coronation WMC, The Village (lower end of Castleford Road), and mainly Wakey fans in The Hark to Mopsey, St John's Terrace WMC (Wakefield side of town). It was fairly evenly split in the town centre and the Comrades Club.
There were also a decent amount of Fev fans.