Today I got
this gooseneck to play with
It holds well even the heaviest Mimas. But there is some swaying involved when turning pages. But no big deal. Still, perhaps I should also get a foot pedal. I could use it with my hand, not necessarily with a foot - or, as it might be the case - a bluetooth keyboard is cheaper and more useful, who cares about its ergonomics.
So, to read directly from a usb flash stick - it is still safer to have it at the top, not at the bottom. Cool Reader allows upside down orientation. The default reading app of Mimas/Alita/Ares - does not, it seems. But they all have cards anyway, so OTG workaround is not needed.
And Onyx Boox Note 2's default reading app allows 180° orientation - so everything is fine.
BTW, with a bluetooth keyboard, do I need some special app, or android > 4.0 handles everything so that Page Down / Page Up keys turn pages in every reading app?
And probably sound +- keys would work too, because they work on Mimas to turn pages.