I have a cake in two weeks and the plan was a 18'round bottom dummy cake followed by a 14-10-6 square real cakes.... OK the bride just emailed me wanting to make the dummy a real cake because they need more servings now. I told her that this will give her practicly double her origanal serving and offered to do a sheet cake or even cupcakes to make up the extra she needs. (OH, there is also to be a grooms cake but she does not want that counted because she thinks her new husband will 'save' it)
Now she say's she still wants the bottom to be real and to make the 10' a dummy. well.... I don't have an 18' round pan, I would be willing to go buy one though... BUT I just measured my oven and it wouldn't even fit if I did have one!!!
I need to get back to her but I'm not sure how to tell her I can't do it. I

I need some other options to give her. she need 170 servings and she wants 4 tier.
Sorry this is so long! I hope it makes sense!!

Just tell her you don't have the oven capacity to make an 18" round and that when you suggested that size it was for a dummy.

Offer to make a 14" cutter cake for her extra servings.

There is no easy way to tell her your oven can't take an 18" pan other than to just get it out there.

I have an 18" diameter 1/2 circle pan that I believe is a Wilton pan. It fit in my oven fine. I made 4 one half circles for 2 tiers and alternated their orientation when I put it together. This made it more stable.

You could always just do real cake for all 4 tiers. 8,10,12,14 inch would give you 196 total servings.

What about offering two "side" cakes...8 or 10 inch size? Omit the 18 inch dummy, of course.

make sure you can also deliver such a big cake too!! 18" iced and on a cake board big enough to fit it is going to pretty big and also needing room for the other tiers unless you stack them before delivery.

Yes, delivering such a large cake will be a problem. Inform bride it's not very feasible. Remember you will need a board at least 21" in diameter - no cake cardboards that big (wouldn't be strong enough anyway).
I had 1/2 round pans - both 16 and 18. Neither made a *round* cake I had to cut a 1" strip to put in the middle - What a pain

You have to be the one to lead the bride when it comes to baking.
I just had a 'light bulb' moment.....maybe you can find an 18" styro wreath(sp?) and put a cake in the center?

Well your other problem is that a 14 inch square will hang over an 18 inch round by about an inch at each corner~~if I'm reading your order correctly.

So there's a lttle more to it. Good thing you got two weeks huh.

I mean when brides get a certain look like that in mind like your round topped by three square cakes--they often have to buy many more servings than necessary.

6-10-14- are a 128 servings. a 16" alone is 100 servings, so I can only imagine how many servings an 18" is. Thats a lot of extra servings to pay for. 6-9-12 & 15 will give her about 186 servings.