We can't assume there won't be any WW promotion when we don't even know when it will start. I still think Spring is out of the question, because, after all, SOMETHING would of popped up by now if the album was going to be released in March or April, even May. So, at the earliest, I expect June or July. I doubt the residency would start RIGHT then. If anything, I'd be more keen on thinking that it'd start maybe a month or two after the album release. So, early 2014? (If the album gets an October/November release).
I'm sure they'll invest in a hefty promotional campaign (perhaps one that wasn't too prevalent in Britney's previous tours) that will attract buyers and merchandising itself is VERY lucrative. T-shirts, DVD's, jewelry, shoes, hats, and all that stuff can bring in some nice coins. 
