When I owned my FW900, and hell, for my Artisan and F520, I never messed with any of the geometry setup procedures as it's more often than not unnecessary. The only time I did the full geometry setup was when I wrote that guide a while back on doing the geometry for all of you.
But anyways - the only thing a monitor typically needs to have done is a touch up on the dynamic convergence (and even then most monitors don't need it unless you're just really picky) and a recal of the white balance. Geometry, landing, etc, shouldn't really need to be changed unless you're an ultra perfectionist. For 99% people out there, I'd say it isn't worth it and you're probably going to ruin it more than fix it.
To keep things into perspective, deflection yokes on flat CRT's are literally round pegs steering electron beams onto a square face. It won't be perfect. Also, these monitors have tighter deflection angles to keep the depth of the monitor down. The best geometry I've ever seen is from a CRT projector and that's because the tubes are deeper than they are wide/long. My 9-inch PVM also has damn near perfect geometry probably because of its smaller 70 degree deflection angle (the 14 inch monitor has a 90 degree angle and has the same depth as the 9 inch).
My 2070sb has 4 additional geometry variables to play with and I've gotten it nearly perfect on my 2 units. No ovals at all. It's a shame that Sony didn't expose such settings in the OSD. Does WinDAS allow for more adjustements in this area? A friend of mine has bought an FW900 that seems to be fine except for absolutely unfixable geometry.