Just to indulge the premise behind this kind of analysis for a moment - I guess I'd question as to why the anime view of this feat would be used as your default for making this kind of measurement, rather than the manga. The manga is, after all, the original work. Even if you prefer the anime, this should presumably be at least straightforwardly convertible to evaluate it in manga source material, since the same feat is depicted there.
And then, I'd question which specific drawing from the manga you'd decide to pick as the equivalent of this to make your measurements, since there are a few of them, and there are clearly visible variations between panels as to how large Goku is relative to the rock, and even as to what the rock generally looks like. Which is, frankly, unsurprising. And then I'd question, since we see this variation, how you can have confidence in applying this level of analysis.
Even leaving completely out of account the basic propriety of this kind of analysis in theory (i.e., that you can't analyse the work to this level of detail and expect to get a 'scientific' answer because there clearly wasn't any sort of 'scientific' thought behind how much weight Goku can be shown to move), how can you reliably apply it on conflicting data? Even Goku isn't drawn at the same height relative to other characters from one panel to the next; how can you use this kind of inherently variable depiction and expect to get an answer that will convince?