With Advanced House Level 1- 9, and Atlantis Rising, Extra fast training ( RT19 ) is still nice, but Common ( RT01 ) and Uncommon ( RT02 ) training just became more useful for leveling. Advanced House, and Atlantis Rising, shifts much of the burden from Hero XP per recruit to Hero XP per 1k food.
Harpoons will also consume 1 hour of food production ( see notes ), so Extra fast ( RT19 ) may reduce your harpoon budget.
You can use the recruits from Advanced House Level 1-7, and Atlantis Rising, to more easily run 2x to 3x Legendary training to get Classic 4* / 5* heroes faster. On average a 4* hero every five days ( 2x trainings ) or an average of every 3.3 days ( 3x trainings ).
4* heroes are the backbone of Empires and Forge Level 17 is the backbone of Class quests. So Legendary training and Forge Level 17 are important goals.