I have an order for a 3 tier square wedding cake to feed 80-85 people. What should the dimensions be? I have an idea of what size pans to buy but not sure. Walmart has a set of 3 by Wilton but not sure of the dimensions. Also, any advice on making it and delivering it from your experiences?

A 6" 8" 10" would feed 100, including the servings on the top tier. (some couples save the top tier to freeze for their anniversary)

The set at Walmart is bigger than that.

I like more than a 2" difference between tiers because it looks more graceful to me, but square cakes have so many servings that if you went up much in size, you'd end up with tons of extra servings.

Here's the Wilton chart: http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

You can find coupons online for Hobby Lobby, Michaels and JoAnn, which you could use to buy your pans. That comes out cheaper than the set at Walmart. I've looked at it before but I didn't care for it because the corners were so rounded. If you want to spend a bit more on your pans, you can get some with nice sharp corners...the Fat Daddio square pans are really nice.

About delivering it, you've basically got two options, to deliver it already stacked up with a center dowel, or to deliver it in three sections and stack it when you get there. You can put the dowels in ahead of time so you don't have to do that at the venue. If you do it that way, you don't need a center dowel. I like to deliver unassembled because cakes get really heavy when they're all stacked up, and besides if you have to slam on the brakes on the way there you're likely to lose the cake if it's already assembled.

So you've never made a stacked or multi tiered cake before?

Here's a wilton page on various methods of assembly: http://www.wilton.com/cakes/tiered-cakes/

Here's the wilton wedding chart to show you how many servings in a pan. Keep this handy. You'll use it often: http://www.wilton.com/wedding/wedding-cakes/wedding-cake-data.cfm

Here's my "How to Cut a Wedding Cake" to achieve these servings: http://www.cateritsimple.com/id10.html

Here's pics of cut pieces of cake to show you that a 1x2x4 piece of cake is NOT paper thin: http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1156785

HEre's a thread with photos on a dowel cutting method: http://www.cakecentral.com/cake-decorating-ftopict-434013-dowels.html