First I think you have to go to:
options => preferences => character sets
and ensure cryllic is ticked. This means it will
appear in the charset drop-down menus.

Then for composing in cryllic:
right click an account => properties => templates (new message)
There is a drop-down box where you choose the charset.

For viewing mail, I think it is like a web browser.
Just as a good web page will tell the browser which encoding to use, a good email will also include this information in its header. So you should be able to leave all the folder viewing options at 'none'.

I don't know what the option 'view => character set'
does. I think it is a manual 'over-ride'.
'autodetect' seems to use the text itself to guess
what encoding has been used for the email.