Does 'best' mean the highest power?
1) Well, the highest power would be the 'n' flag in the bot users file.
'n' denotes an owner (highest)
'm' denotes a master (2nd highest)
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'v' denotes an autovoice (some low rank)
going towards lower access flags
2) Another would be this in the .conf file of the bot:
# Un-comment the next line and set the list of owners of the bot.
# You NEED to change this setting.
set owner "awyeah"
This would be basically greater than 'n' also as this is the permanent owner, since generally one person can have this (which would ofcourse be yours if it is your bot). But you can give 'n' flags to other users as well, so in my case this would be the highest.
Although I am not sure about the access differences these both have, generally the same if I might say as distinguishing between them is difficult because generally to one extent they are almost the same. There is no clear explanation of what difference acceses the 'n' flag and $owner variable hold yet in detail.