As I'll be doing 3 flavours of the trilogy from my captured source, XviD, PAL and now NTSC I tried an anamorphic NTSC clip and it's looking very good (apart from the horrible 3:2 pulldown needed to view on an NTSC screen):

edit: playing back cleaned up clips I've been noticing something's not quite right, the aspect ratio wasn't spot on, doing some measuring of pixels on the captured source it turns out I'm working with 2.293:1 footage not 2.35:1, just needed to increase the PAL anamorphic image by 10 pixels (NTSC by 8 pixels) and it now looks right