We're having a 4th of July party and I'm thinking about making a white cake with red and blue jello to make it red, white and blue. I need at least a 9x13, maybe slightly larger and I'm not sure if I can make a jello poke cake that size and layer it (red one layer, blue the other). Any thoughts or experience on this?

If not doing a layer cake do you think I could do one layer and just put blue jello in some holes and red in the other or will it turn into a mess?

Just making sure I have this right. So you are making two 9X13 cakes, one a red poke cake, and the other red right? It has been done. http://www.copykat.com/2009/05/03/holiday-poke-cake/ This one does those colors. You just have to let each set before unmolding them.