Since I cannot reproduce this very noticeable judder with the above script, I made a few tests...
Could it be that for your conversion AVStoDVD executed DGPulldown on the converted M2V? Because this is what A2D always does when the target is PAL and the source is either 23.076 or 24 NTSC progressive (and PAL speedup is not specified). To avoid this you need to rename the DGPulldown folder to something else temporarily.
Anyways, I downloaded a demo trailer with a lot of horizontal motion and converted it using 5 different methods. The results are here:
https://we.tl/t-97Xpu5NCjh
Please tell me what you think...