Found a treasure trove of classic videos from a guild known as <Rising Ascension> on Povar server.
They have a ton of videos of raid force kills and push is extremely limited...
Zlandicar - It looks like their strategy is to push him into a wall to pin Zlandicar, look how long it takes their entire raid force to push him up the little cliff, looks to be 30+ people pushing and it is extremely gradual.
Gorenaire - This is pretty laughable... Entire raid pulls him to what looks to be hidden valley, Gore stands still the entire fight. There is no 'PUSH TOWARDS KC!!' Unfortunately this video maker was feared early for a large portion of the fight, but you can see Gore basically stood still. Interestingly, he types 'MEEEP!' when feared, I thought on P99 it disables chat when feared? Perhaps a separate bug report...
Cazic Thule - Again, a fight where a ton of melee engages and he barely moves. You actually do see some push going down but man is it slow compared to P99. You can see a stretch where this video maker is starring at Cazic's foot (not moving the camera) and it is a super slow slide.
They do have a Klandicar vid and some Sleeper's Tomb videos too, but they appeared to wall pin or have some 'even push' on both sides, and Klandicar he remained feared for too long to make an accurate determination.
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NPC Knockback test video - I don't know how accurate this video is, is obviously someone with their own EMU or something, but he is testing push values. Take it for what its worth.