An interesting thing. As we know, currently Wu Heir can indeed create real flesh with Bodily Dao. And although it wasn't said anything about real flesh when we use the Heavenly Palm against Su De, if we assume the palm's avatar had a similar weight to flesh and keeping the proportions, it'd weight 14.171 metric tons. And this is its weight alone, even disregarding its descending speed(That must be fast enough for Su De to not escape), Su De, even before her Tyrant Form, managed to withstand for quite a time against it.Your system is very good indeed but I'd say that using the Bull's Spirit as a initial metric is quite wrong. Because Wu Heir is lifting/kicking a powered opponent that weight 6t by base rather than a inanimate object that weight 6t. You can think it's stupid but not only in PoMA but rather many fictional works lifting a powered opponent isn't solely based on their physical weight, we have the proof in the scene against the Bull Spirit per se. Wu Heir at max(Male + 6'6 + Muscular Body-Type) must weight in the range of 220~260lbs, yet if you pass the 34 STR check against the Bull you can stop his charge without moving a single step.
In any case you can use as a base metric the values shown in the very start of the book when Wu Heir, as a mortal, is going to train. At 8 STR we can lift a 700lb rock. At 10 AGI we can complete 100 flat meters in 9 seconds. At 10 CON a "normal" knife(I think) completely fails to cut our skin.
And I'm being very, very orthodox here. Wu Heir can shapeshift/materialize with Elemental Dao at will. What if he created a Heavenly Palm of this size made of steel and launched it at Mach 3 towards Ruo?

Not now, Totenkopf, not now...


