Anamorphic PAL 4:3 (576i) - least lossy resolution for web publication?

[Bubblevision]

In the past I have downsized and published my 4:3 PAL videos (720x576 interlaced) as 320x240 or 640x480 with PAR of 1 (square pixels).

With increased bandwidth I would now like to publish them in a Flash player at the least lossy resolution. I am most likely to use x264 codec within MeGUI using TDeint for deinterlacing and Lanczos for any resizing.

Which of these methods would result in the least loss of quality in the final displayed video?

1. Resize to 768 x 576 (PAR 1)?
2. Resize to 720 x 540 (PAR 1)?
3. Maintain 720 x 576 and signal PAR of 1.0926 in the mp4 file?
4. Maintain 720 x 576 (PAR 1) and stretch to 768 x 576 in the Flash player?

Further, if I choose option 3, does the following AVIsynth script look about right for MeGUI to signal the correct PAR?:

AviSource("d:\fs.avi")
global MeGUI_darx = 4
global MeGUI_dary = 3
ConvertToYV12()
TDeint(order=1)

[jagabo]

Native resolution with PAR flags will give the best result (as far as the video file is concerned) but some players may pay no attention to the PAR flags and quality of resizing for final output will depend on the player. Resizing to 768x576 with square pixels would be safer.