Have you set the 360 Console to it's max resolution? The panel is a Native 1080P Fixed Pixel Display so you want to try and match the console settings as best as possible with the panel since you lack the HDMI version - I do not understand calibrating the Game Mode settings - let the console passthrough and the panel is going to do the best possible to get you to 1080P as it is a Fixed Pixel and there's not a damn thing wrong with 1080i with a video game.
I've never had to calibrate anything on my 360 other than the console settings to match my panel so I do not understand the purpose other than matching the best possible passthrough and let the panel do it's thing.
I choose the max resolution settings and let my Sharp handle it and I have absolutely no need to calibrate anything in the gaming whatsoever and Halo3 is like playing inside a wide screen Movie often.
Good Luck but set the resolution and let the panel do the work I cannot imagine having to reset colors and such unless your dimming in the options of the game menus not the panel menus.
