newcastlecycling

I also find myself sprinting then coasting then braking a lot on Friday nights.

I agree with what Mr Cox esp has typed.  I spend a lot of time watching what guys like Bill do when they race, for they have forgotten more than I will ever learn. 

The only thing I would add is that there are very few reasons to brake at KI on a Friday night - one is to go around the witches hat and the other is in an emergency.  You should be regulating your pace to match that of those around you by anticipating what is happening, without braking and without surging.  If someone is repeatedly changing their pace then that creates potential danger and generally stuffs the race up.  It is one of the reasons why I find C grade more danagerous than B grade.

4 abreast is not of itself dangerous.  It only becomes dangerous if people do dumb or unpredictable things, or in anything under B grade, get too close other riders and those other riders over-react.