[markom]

Orange background shall make pages appear too dark for someone's liking for reading on e-ink reader, so in this case I preferred b/w option without applied threshold (copy mode; native output disabled and color also disabled) but with contrast -cmax on 3 or 4, because there is no contrast command in Kindle DX(KPV reader), just gamma option to make pdf text darker and night mode.

This way, using contrast command, background was whiter than with color pdf, words of different colors appear darker or visually different and table nuances are preserved better than with white-threshold command.

Pdf then just quickly cropped using pdfscissors, briss or k2pdfopt and then if we are not satisfied with the flipping speed (e.g. at landscape mode), we can quickly optimize it in k2pdfopt for landscape(fit width mode, the same values for M92 as for Kindle DX).