Some people treat the Kilo as a fitness test of sorts. They do it maybe once or twice a year at a local event or whatnot. You'll never see your best possible time that way.
In general, the Kilo is a race that takes lots of preparation to perform your very best. Even moderate preparation will yield nice gains.
If you break the Kilo down into 4 areas:
- Standing Start
- Acceleration to top speed
- Speed endurance
- Mental toughness
Then train the first 3 individually (the 4th gets trained along the way with the others). The top 3 can be measured and tracked using advanced bike computers that save data for download. No need for a power meter. In your training and testing, you'll find what gears work best.
Once you find a good program that trains those areas sufficiently, then they should all come together for only a handful of test kilos and big event kilos each year. IMHO, the worst way to train for kilos is to do kilos. Why? If you are doing kilos properly, it's brutal and may lead to actual clinical overtraining. If you are not, then you are just doing 1K pursuit efforts.