Which story should I write next?

In the span of the last two days, I complete revisions on my manuscript (CHICKEN SHACK), sent it off to my agent and began a new book. 

Actually, I've started writing two new novels since finishing the initial draft of CHICKEN SHACK.  I'm thinking of one of them (BUDO) as my primary book (at least 2,000 words a day with a goal of being finished by September) and the other (BETTY BOOP) as something that I will tinker with when I need a break from the first.

I'm fortunate, so my agent says...