I get much better results with
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my chair seat angled down a little, to open up my abdomen
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my monitor(s) higher than recommended - centre of the monitor level with my eye: forces my head up to align my spine
I have also (to great hilarity among my co-workers) taken all the numberpad keys off my keyboard, aand blu-tacked my trackball onto the now-vacant space so I don’t have to reach off to the side for it.