You can pick them very tiny if you want to,they are so good when very small, sometimes I would take part of the stalk , about 3 inches when the squash was about 2 1/2 then slice down the the squash and straight down through stalk splitting into it two as you go , then cook them like that,stalk and all. I like them Tempura battered but you can do it anyway you want even raw with a dip at that age. The more you pick them the more they grow so picking some very tiny ones increases your yeild over all.
XX Jeannine