There are several in my posts ;-)
Foe encoding I keep 720x576 SAR 5/4 and force DAR 4:3 if necessary (not square pixel, PAR=16/15)
If upscaling to HD I use 1440x1080 and add 240 borders each side: so square pixels (PAR=1) with SAR 16/9 and DAR 16/9
Attached 2 xls files; sorry some text is in italian, but may be you can find them useful.
Addendum: if you work with avi lossless files (HUffYUV
and others) you may need to add to the the DAR with something like
ffmpeg -i <file>.avi -aspect 4:3 -c copy <file>_dar.avi
so any tools working with it will have correct info