Hello! It's been a while since i've last made something on Stencyl

Working on an iOS game prototype and i've run on a bug/issue with screen resolutions:
1) The resolution settings are totally obscure.
Case one: I want the game to be 640x960 and run as 640x960 in flash, downscale to 320x480 on iPhone 3G. My art is high rez.
What settings should i choose? 640x960 and Scale x1? Or scale x2? What is scale anyway?
Case two: I want the game to be 640x960 and run as 320x480 in flash, downscale to 320x480 on iPhone 3G. My art is high rez.
Same problem - what settings should i choose?
2) When importing an actor's image i can choose it's scale x1 or x2. Not comletely clear what i should choose, but the problem is: i can not change that later. I have to delete the animation and import it again if i chose wrong.
3) In an animation frame import window i can choose x1 or x2 scale, but that only works before i select the image.
Case: I open animation import window and see scale set to x2 (Retina). I import an image, and then set scale to x1. Press "Add", but the image still adds as x2.