How long should gender reveal party last?

So this is my second pregnancy and with my first I didn’t have a gender reveal and I would love to have one. I find out the 4th of June and was going to have the reveal on that Saturday. (I believe the 9th). How long should the reveal last for? I was thinking 3 hours, is that to long or to short? It’ll be a bbq/cookout style and I’m renting out a park pavilion.

Thanks in advance