The only other thing you could try is to swap out the gauge.

240's usually run around 1/2 or slightly less.

The gauge is no more than an idiot light, it just tells you relative temperature nothing real accurate. The important thing is that it is consistent and you know what normal is. If it climbs slightly while you are working the engine harder than normal.

I wouldn't worry too much. It sounds like your cooling system is up to par, but for piece of mind you could get an infrared thermometer and check the outgoing temp of the radiator. Dan