Hi,
Get an infared thermometer and check the temps of the hoses going in and out of the radiator during the time you think you are overheating. I guess the question I have is are you physically overheating or is the gauge just telling you that you are. The gun will really tell you where in the system the temp is higher and lower so you can isolate what part of the engine the problem is at.

Just a side note - Are you running the system through your heater core? If so you could have a blockage in your heater core that isnt allowing the fluid to travel as it should. I recommend two things:
1. Bypass the heater core - Just unhook the hose that goes into the core and hook that up to the engine block - That will remove the heater core from the system.
2. I personally would not fully remove the thermostat. The coolant needs to slow down a little bit to get proper cooling in the radiator. Removing it all together means the coolant wont spend as much time in the radiator getting cool. I would remove the center portion of the thermostat and even drill a hole or two in the metal plate of the thermostat and then re-install it.

Also check your radiator cap and make sure its the right pressure rating. Perhaps it is not.

Good luck