You can set the printable area via T/B/L/R margins in pixels, and you can get the screen resolution via eval $(fbink -qe), so you should be able to do roughly the same kind of things with a bit of maths

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The only thing you won't get beforehand is the exact maximum pixel height of a specific font at a given point size, because that's only done from inside the printing loop.
TL;DR: You can actually *only* do pixel positioning

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