Yes it should work, but MipeTDM's comment might hold some hidden wisdom
Although in saying that, as someone who has run car and bike engines without thermostats in place, it is nice to take control of the upper temperature.
I suspect though that the 900 radiator isn't completely sufficient for hot weather in traffic, I know mine isn't and the fan is coming on and off very often. Perhaps a larger radiator with passive cooling would make it more predictable when it came to the cooling systems response to a change of thermostat.
Perhaps the problem is that because the system is a well engineered compromise, the fan is coming on so often that the perception of it is that the bike is getting hot quickly, and could therefore possibly overheat
I'm still waiting for my genuine bought on the internet psychology degree to arrive.......