piggyqueen wrote:I don't know which one I'm supposed to build for my palisade.
You should have at least one of each.
Visitor gates give other people the visitor debuff if they enter them, so they are harmless if they enter through it. But no one in combat can enter the gate. So if you are being chased in combat, you also cannot enter the gate.
The normal gate does not give the visitor debuff, so anyone that enters it can freely steal and destroy everything. It should ideally only be used in emergencies or if you feel 100% safe in going out and immediately closing it behind you.