Q.Sugar baby watermelon
When self-pollinating sugar baby watermelon does one need to pollinate every female flower or just a few of them? I am growing them in five gallon buckets and have an unbelievable amount of flowers, but I understand that I should limit the number of watermelons to two or three. I would really appreciate any help or information. Thank you.

Pollinate them all to help the chance of them producing fruit.
https://www.gardeningknowhow.com/edible/fruits/watermelon/growing-watermelons-containers.htm