I uploaded a video to youtube that shows some video artifacts happening with the scan doubled video.
The entire video shakes as if interlaced, but it’s not. Original res 320×200(15.7khz), doubled to 640×400.(~31khz)
There is a colored wavy pattern across the white sections.
On a monitor directly attached to the amiga, the screen is very stable, crisp, and nice looking. 🙂