This is the rear of my 450. This is where i mounted the receiver.
This is how i mounted the Naza controller and gps. Kinda hard for you to see but i found center on the bottom board not the top, and i moved some lines over so you can see line on the Naza controller, that line on the controller needs to be centered vertically, i used the symbol in that line as center point as well.
looking at the GPS it is facing forward to the front as it should but the arrow is off of being straight from vertical position. That is because the quad did drift so i turned it slightly, prob between 10 and 30 degree. You will also notice where i positioned the gps, i put it back further to be away from power and control board but within specified limits.
This is the front , as you see power is mounted there as from what i read any power source near GPS will throw it off which it originally did until i re-positioned everything. The LED will be mounted here with a clip i ordered from shapeways 3D printing.
You may need a power source by the sounds of it these are some i use.
This where is just positioned my battery, which i tried to position to center as well for good balance.
I know this is way off topic on what you asked but thought i would just share. I do have a 450 quad similar to this as well but i used a naz32 flip board and flysky-t6 and a transmitter. I can take pics of how i set my controller for switches positions and stuff up for you it may help you a bit but mostly everything is done on naza controller.