Realistically, one can only achieve level 30 post time skip.
Now unto speculation:
Bow Knight (as we know): Lance - C, Bow - A, Riding - A
Falcon Knight: Lance - A, Flying - A
Wyvern Lord: Axe - A, Flying - A
Dark Knight: Lance - C, Reason - A, Riding - A
Holy Knight: Lance - C, Faith - A, Riding - A
Mortal Savant: Sword - A, Reason - A or S
Gremory: Reason - A, Faith - A
War Master: Axe - A, Brawl - A
Great Knight: Axe - A, Heavy Armor - A, Lance or Riding - C
Dancer - win the dance contest or Sword D+