Oh yum!! I am going to try the root beer in a vanilla cake mix for a root beer float type of thing.... an the orange would be amazing with the chocolate like a chocolate orange slice yum! I wonder if you could use diet soda and or sugar free??
The issue with needing to bake longer is due to how you measured the pop. You can't use a scale to measure fl. oz only oz (dry). For liquids you have to use an actual measuring cup. one cup = 8 fl. oz.
My mother went through a phase a few year's back where she made these at least twice a month. (special occasions) They're actually quite good if made correctly.