Type /reload in-game, then pick your LogKing.lua. It holds the whole night, however large — no copying, no pages, no size limit.
/reload
LogKing.lua
Type /lk file in-game and the addon prints the exact path. It looks like this:
/lk file
…\WTF\Account\ACCOUNT\Realm\Character\SavedVariables\LogKing.lua
The client writes that file on /reload or logout, never mid-raid — so reload before uploading, and after each boss if you want to be safe against a crash.
No logs yet. The first upload lands here.