I'm an idiot. All I needed was the XOR gate. The RS NOR became superfluous when I changed from buttons to levers.
Here's something. I don't have time to make anything better. The not gates on the bottom floor are only there so that the gate is closed when both switches are in the same state, so feel free to remove them.
Here is the save file.
Mediafire wouldn't let me just upload the whole folder, so you have to download all of the files and place them in %appdata%/.minecraft/saves/OWFGATE
Anything in a folder must be placed into a subfolder of the same name. The folder Data is empty, but you need a folder with that name so I made it to remind you.
EDIT: By the way, the wool is colour coded. I can't remember which colour was which, though. You should be able to work it out.