I honestly think that the beginning phase of your wedding planning should involve diagramming the event space. With that information in hand, you can easily rent the correct tent size, know your number of tables needed, tell the florist how many centerpieces you need, and visually see where large decor pieces should go, amongst a lot of other things!
Table shape and size dramatically changes the number of guests you can fit into an event space. Also, different table shapes require different linens, and the price difference can be hefty. So although you may love the idea of square tables, they may cost a lot more than you budgeted for (it takes 2 linens to cover them in most cases). So keep all of this in mind when selecting your table arrangement! Also, in our local Montana wedding market, the only swag tents you'll find are the rope & pole tents, and as you'll see below, your table layout must be changed to accommodate the center support posts.
I'm going to use the 150 guest count as an example and show you some different diagrams and things to consider! I'm using a 40' x 60' tent in all the diagrams below, so we can compare apples to apples, and all layouts show 6' round tables (10 people per table). Also, There is no space in any of these layouts for a gift table, guest book table, DJ table, etc. So when you add tables for these purposes, guest seating needs to be removed accordingly.
DIAGRAM #1: Plated dinner in a canopy tent (with no poles).
In this layout, to make the head table prominent (as it should be, we've left if on the East side of the tent. You can seat 160 people according to this diagram, but keep in mind that the tables in this diagram are TIGHT. Guests will be using the dance floor as the open space to navigate the room.
Table shape and size plays a HUGE role in how many people will fit into your tent. This same size tent with 5' rounds in this same layout will only accommodate about 145 people. With Rectangular tables, in "Bier Hall" seating (as I call it), will seat nearly 185 people.
Also, when you have over 150 guests aged 21+, and you're offering a full bar (liquor, wine & beer), it's a smart idea to have 2 bars. One can close after cake service, when some guests leave, but to accommodate that initial rush during cocktail hour & dinner, we strongly suggest having 2.
DIAGRAM #2: Plated dinner in a rope & pole tent (with center poles & ceiling swag).
Although you may like the layout above, it cannot be duplicated when you use a rope & pole tent. The red circles indicate center poles, which support the ceiling in this tent style. This means the dance floor must be smaller, and the head table should move so it's in a more prominent position. Simply moving a few tables around to accommodate those center posts means that you can only seat about 150 people in this setup.
DIAGRAM #3: Buffet dinner in a canopy tent (with no poles).
Serving a buffet style dinner IN your tent dramatically reduces the amount of seating available. When guests are expected to get up and move throughout the tent, you especially need to make sure there's ample room to walk between tables. You also need to leave plenty of space for your buffet tables, not only so a line can que, but also so the buffet servers can efficiently service & refresh the buffet. Keep in mind, just like the bars, when you reach 150+ guests, you typically want to add a second buffet for more efficient service. But because this layout dramatically reduced the seating in the tent (to about 130 people), we're able to stick with one bar and one buffet with a properly sized dance floor.
DIAGRAM #4: Buffet dinner in a rope & pole tent (with center poles & ceiling swag).
This last diagram is the least ideal of all the setups. Yes, it fits 150 people into the event space with a buffet, but we had to reduce the dance floor size due to the poles, there's only one bar, and there's only one buffet. We managed to increase seating by moving the head table to the north side of the diagram, but just because you can fit all your guests according to a diagram doesn't mean you should! If a client were interested in this diagram, I'd strongly suggest going up one more tent size, so the tables could spread out a little bit, and we could add a second buffet and bar.
Want to experiment on your own? Go to www.weddingmapper.com and check out their free online tools for mapping out your own wedding! Be sure to leave plenty of space between your tables, and add in all your important elements, like the cake table, gift table, bars, buffets, escort card table, guest book table, etc.