Warming up for a race

I recently read an article on the importance of warming up. I have started beginning my workout by doing a 5 minute swim at an easy pace (usually about 16 or 18 laps), then a brief rest, then a 300 moderate tempo warmup. I then follow this with 4x50 on the kickboard. That means I am doing about half a mile of warmups. I then get into my workout, which is usually intervals of 100s, 50s, and 25s, swum mostly at anywhere from 80 to 100% of maximum effort. My question...on the day of the race, there is usually one hour before the meet starts. How much swimming should I be doing? Should I do my full warm-up, so all the kinks and lactic acid are worked out of my muscles? And what about between races...Let's say I have a 50 freestyle and then a 50 *** a half hour later. What should I be doing in between?