I seem to do the same thing every time I have an order for a wedding cake (I usually do about 4-5 per year and so its not my habitual) I consult a million different portions charts to eventually attempt to feel comfortable with the size of cake to make in order to ensure that they have enough.

The couple has invited 170 people to the wedding

1) Do you wait until they have all of their confirmations and ask them to send you a final count or do you base the cake on the number of invites?

My cakes are the standard 4'' high and they want all tiers to be the same height.

2) what size rounds would you use?....they initially wanted a 3tier because they like the look but I could convince them on the 4 tier but no bigger.

Thanks for your input!!

1) Do you wait until they have all of their confirmations and ask them to send you a final count or do you base the cake on the number of invites? No, your client should decide how many servings to order (depends also on their budget). You can only guide them, but it is their decision. Check this: http://cateritsimple.blogspot.com/2009/07/debis-60-rule-or-why-rsvps-dont-work.html

2) what size rounds would you use?....they initially wanted a 3tier because they like the look but I could convince them on the 4 tier but no bigger. A lot of bakers use this: http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm