We avoided using numbers and gave our tables names, so the hierarchy issue was gone. I placed the 2 tables of parents / immediate family side-by-side, equidistant from the head table. I also had a table with the spouses of the bridal party and the MC and her husband which was the closest to the head table (partly for logistics to make it easy for the MC to get to the podium as needed).
Are you saying between your parents versus his, who should get Table #1 or Table #2? If we're talking "tradition" then it can swing many ways. Typically the bride's family is the host and pays for the wedding so etiquette would suggest Bride's family is Table #1. But some people believe that men are the head of the house and since you're marrying "into his family" and taking his last name, his family should be Table #1.
Of course, I assume you're a modern couple who don't care for such patriarchal rules so you can either give it to the side that will less likely make a stink about it, or don't assign any table numbers to the family table. Just call it the EllyFam table and the KooshaFam table.
The last wedding I attended over seas, the seating chart was created to have the two sides separated and not mingling with other family. When seating our guests, the parents and adults from my moms side were seated together and the family were seated as mixed with 2 brothers seated at different tables with family and in laws. You create the seating arrangements as you see best to your vision.
I put my parents at one table and his at the other, and our kids are in a table in between. Ideally for me I’d like my parents served dinner first after the head table since they’re paying for our wedding.
I have never heard of any etiquette that says who goes first. I think as long as it works for you that's the best solution. I'd put each family closest to your table we did hubby's dad to one side and my mom to the other. It worked for us.
Ours is like a U shape so the side the groom is sitting I put his family on that side and the side i'm sitting I put my family. My friend had the head table and then in front of them as a t shape had placed the parents and brothers and sisters at that table and the rest were rounded tables around the Tshape.