Well, there is a technical difference between a limit of 10 requests/minute and 100 request/10 minutes. The average is the same, but the later allows for 100 requests in a minute followed by 9 minutes of nothing, whereas the former does not and 1 request/6 seconds is even worse
Flippers wouldn’t help really given how horses actually swim, they kind of kick back with each of they’re legs in a sequence similar to a trot. Their hooves already have a bit of a hollow which likely helps with swimming. Honestly though horses are pretty good swimmers, because they have huge lungs which helps them stay afloat with ease