Wow, 400 for a swimsuit.
Can understand you want to keep that for the official contests and events.
Perhaps you could buy a cheaper, less quality one for the training?
Think you would improve immediately on lap times, that belly causes a lot of drag in the water.
For consistency with times it probably would be better to also train with a swimsuit.
I assume this video was made for analysing purposes, that's why I mention this.
It would be the first thing I'd say after looking at this video if I was trainer.
In the end most important thing is to have a good time and get some excersize.