Need help with price and size of this cake. :)

I would say with regard to size you would need to ask your customer what size they want it? How many are the feeding etc? Then once you know the size of cake you will need you can work out the cost of all the ingredients and decor and that will lead you to how much to cost once you have figured out your time and other costs. Carved cakes are usually more expensive than round or square as they involve more work. As to how to make it, this is a fairly common style of cake so you will find loads of examples online, you can either carve it or use semi sphere pans.

I make mine to customer request by using round cakes to start with and carving them. I do not deduct any servings in my charge to account for the extra cost of carving it. I do the belly in whatever size cake they need to feel their guest, but make it a 6 inch tall cake. I keep things proportional by doing each of the breasts about half the size of the of the belly but only 3 to 4 inches tall. So, for an 8 inch round cake, in the belly, I do two 4 inch round cakes in the breasts. Then I just use the serving sizes for those pans and charge my price per slice. I do these cakes in fondant because it looks nicer. So, for the breasts I would figure out how many servings in each of the 4 inch round cakes and multiply by my fondant slice charge. For the 8 inch round belly, as a 6 inch double barrel, I would figure out the the amount of slices BUT I would change my price by slice by multiplying it by 1.5 because it is 1 1/2 tiers basically.

Same thing goes for a bigger cake… If they need enough to feed more you could do a 10 inch round, 6 inch high cake and then do approximately 5 inch round breasts 4 inches tall. Then figure out your price per serving.
If you do a 12 inch round belly, do 6 inch breasts and so on and so on.

Hope that helps. :D

Excellent ! Thanks for all your help !