benson I looked at my first ever 4th cat race in 2014 - 52mins at 295W / 325W NP. We were chasing a break down, but failed, finished 11th. Then got 5th, 4th, 4th and was promoted to 3rds
Edit: looked at a later race with no significant breaks and was 245W / 305W NP - pretty big difference not having to chase anything down