Ok, so you think I can leave out "qwerty/яверты" encoding and make only CP866? Will this be enough for most texts in cyrilic?
Depends what texts you plan to read and where they were originated from. Basically CP866 is enough, as most cyrillic textes were made in something like ZX Word/Modern Word/ZX Asm/etc.
Свирепый агрессивно-депрессивный мордовец! Не уверен - не напрягай!