playing orc sigil knight OLY question

ok so if i lvl an orc>tyrant>warrior and then subclass him to a paladin>sigil knight as my dual class... how do i compete in oly and under what? do we still compete under our class specifics like "paladin" "tyrant".. and would i only be able to compete for the tyrant oly if i did this

You can only compete in olympiad on your main class.

In your example this would be the Tyrr Warrior awakened from a Grand Khavatari.