Nick, a balanced Neapolitan bake is never going to happen in this oven- at least, not without modifications, and, even then, I think it's a bit of a long shot, depending on how many BTUs you're working with.
Do you see the floor and dome temps you're currently seeing? Those basically have to be reversed. The only way this can happen is if you have a boatload of BTUs and some form of deflection- some method for bypassing the bottom stone and carrying the heat to the top. Based upon the temps you're hitting, the deflector can't be aluminum either. You'll need either steel or ceramic under the bottom stone, with an air gap. It'll need to be either the same size as the bottom stone or larger, but can't be so large that it blocks the gap in the back.
You're talking about a lot of tweaking/messing around here, with, imo, a very low chance for success. I would stick to NY.