I have a 6 quart KA and wondering how many recipes I can get in without going over!

That's a standard Kitchen Aid mixer bowl size so one recipe of my *original* WASC recipe shoud be all you can get in it at one time.  http://www.cakecentral.com/recipe/7445/the-original-wasc-cake-recipe

Hmmm...okay.  I was thinking that I doubled (2 boxes) it in my old 4 1/2 qt. 

Sorry, I can't picgture how big a 6 qt really is and looked it up on the internet.  Maybe it will hold 2 then.   Don't think I dbld in a 4 1/2 qt - almost sure that would be too much batter.  Guess you are just going to have to experiment.