As for leaving a thermostat out, a lot of people will take out a thermo stat in the summer so coolant will flow through the engine at all times. 50/50 or 60/40 is the best. I just installed a Mugen thermostat and fan switch, my car stays cooler than normal and runs fine.

 

The temperature guage should be at the middle of its range in normal operating conditions - I don't see a problem with that. As far as the blown radiators, I don't know for sure - but you might want to have the water pump checked out just to make sure it is ok so you can eliminate it as a potential cause of the problem (though you don't say the temp is reading high, so the pump seems unlikely to be bad). Other than the water pump, I don't have a clue except that you had three radiators go bad. The higher temperature thermostat allows the same flow as a normal thermostat, it just opens up at a higher temperature level.

 

Right, and you'll want to check that the thermostat is installed in the proper orientation. If it's installed in reverse, the thermo's gonna do pretty bad things.

BTW, stock thermos are 180 degrees for Hondas. The Mugen one is like 158 or something I think...