The ECU doesn't use the o2 sensors on startup because they need to be hot to work efficiently (which is why they have a built in heater). Glad to hear you're happy with the result, but have you tried riding it without bothering with the resistors? I'd do a test with my bike, but since I have the Dominator megaphone map which is presumed not to have o2 sensors Norton will have turned of any fault warning. I suspect it will be the same for you. But please try it. Right now one of two things is happening, the engine is running in permanent open loop i.e. just using the fuel maps in the ECU or depending on how sophisticated the simulator is, it's still running in closed loop at steady state throttle openings with who knows what AFR.
If Norton has disabled the ECU from throwing a fault code without an o2 sensor, you're better off just unplugging/removing the o2 sensor and putting a blanking plug in. I for one would like to know exactly what is going on and whether or not the resistor is actually needed. This is the kind of info that is really useful for the community.
Remember the o2 sensor is only used in steady state throttle openings, it makes zero difference when you're 'working' the throttle, plug a $5 bluetooth OBDII reader into your ECU and you can log a whole bunch of engine parameters whilst riding on your smartphone.