When I moved to this home six years ago, we bought a dining room table that opens to a 54" square. I liked the idea of a square table because I thought it would make for easier dinner conversation, compared to a long rectangular table. I also thought it would make for more egalitarian seating at holiday meals(no issues about who gets seated at the "head" of the table...) I regret to say that it really is crowded when 8 people are dining. You lose room at the corners. For instance, you can't put down 8 standard size placemats for breakfast or lunch and not have them overlapping at the corners. It's also harder to find tablecloths that fit properly. I usually end up having to cut and hem longer rectangular ones. I love the look of my set. It's all wood with sturdy matching fan back chairs and I have a coordinating sideboard. We keep it at the 36" x 54" size for everyday, which gives us plenty of room for 4 people. Bottom line - the 54" square is fine for serving 6 people, but a real squeeze with 8.

its your dining table's fault. standard height is about 30", and yes you sink in some upholstered chairs depending how they are constructed. even though a 'normal' difference is 12" (which would mean a 19" chair for your table), if your bum (and therefore spine) are sinking below the wood frame you are getting less than the measured height. i'd rethink the felt sliders on the table, or else find straight chairs that can be custom made an inch taller. it doesnt matter what the ruler says... you know if you have that sinking feeling..... (we went through this.... fortunately we bought our chairs and table from the same store and werent able to try the sample chairs with our table. turned out the table was higher than all of their other tables. they remade the custom chairs an inch taller and i've been able to eat at the table without feeling like i'm 9.)

Thank you @JustMe, I understand what you are saying about ordering the singles. That certainly is an option. Let me clarify myself....we wouldn't be removing a coffer to hang a light. In fact, we would be adding the coffer. We toyed with the idea of adding a coffer to the dining room ceiling anyways prior to purchasing the light. We are the builders so we can add this at any point before we go to drywall. The ceiling in that room can either be a tray or a coffered ceiling. If we do put a coffered ceiling in this room, the base of the light could be mounted on the beam of the coffer. By doing so, the hanging globes would then be the correct height above the table. Sorry if I wasn't clear in my original post. So I guess my question now would be if the light would look weird if it was mounted to the beam of the coffer?

OK sounds like you have just enough space even allowing for chairs etc. I would tape out the 72" table and width of the chairs just outside of that to ensure you like the walking space if people are seated at the table. Painters tape works great for this.