I need to make a cake for someone and they want the bottom tier a 12 inch 2nd tier an 8 inch and the 3rd tier a 6 inch. do you think it will look fine considering that there is a 4 inch difference between the 12 and 8 and only a 2inch difference between the 8 and 6?

just depends on the decor--a skilled decorator can make any variety of shapes and sizes look great

AWell that is something you don't see every day, someone requesting specific sizes like that.

I think 6-9-12" 3 tiered cakes are so romantic but that's just my personal opinion.

Here are some options if you are interested.

http://cakecentral.com/t/690543/wedding-cake-tier-sizes-opinions-please

6-9-12

http://www.make-fabulous-cakes.com/tiered-cakes.html

Another 6-9-12

http://www.americastestkitchenfeed.com/bake-it-better/2012/01/secrets-to-making-a-wedding-cake/

This site offers options for various sizes.

http://www.rosalindmillercakes.com/rosalind_miller_cakes_blog/read_79453/how-to-get-the-size-right-for-your-wedding-cake-design.html