I will be making a "rainbow & clouds" cake for a little girls birthday this weekend.  I have a 16" round pan that I will be using to cut the "rainbow" out of and 2 9" pans that I will be using for the clouds.   I know that I can use a single box of cake mix (that I will doctor to make rainbow colors ) for the "clouds", but I don't know about the 16" round pan.  Will it take 2? 

It will take more than 2.    I use 2 (using wasc recipe which gives you a little more batter) for a 15.

Thank you so much Debbie!  I will give it a whirl and I'll let you know how it goes!