since iv lernt how to add images to the background in ade9 iv decided to start making adcafs the question is how big do you need the google earth image to be in ade9 to make it accurate

I tend to use several images. A high level image to get the outline and several smaller ones for detail.

Yup, several images is the way to go, though it depends on the quality of the images you can find. I use Bing Maps and Google Earth and take the most recent images I can find.

how do you rotate the runway to fit onto your image plus i go to open stock airport and get errors

not many airport i can do cos it seems the stock ones are propper ones iv not installed any apart from uk200 bristol liverpool and manchester