Track Gearing (Herne Hill Day)

J4mmd any gearing suggestions for the track?

or as this is probably a competitive day(Sun 25th May, 1pm - LondonFgSs Spring Track Day Event at Herne Hill Velodrome) and most will keep their special gearing under wraps to blow away the competition a pointer as to whether my **48/18 ** NO is a good start (i'd be a track novice)

whats the theory, is it to reach your ultimate spinning speed and keep it up for the duration without it being too easy that your legs flap wildly?
or use brute force to push the tallest gearing you can at a reasonable spin?

Your legs'll be going like the clappers - I'd go 50/16