For 50/51 up to 60, forget Leves. They can help, but are not as good as Collectibles. Just make sure that you get gear that lets you have 600 GP and a decent amount of Perception (to reduce the number of Appraisals needed to hit minimum Collectability). Focus on getting the most Collectibles at just above the minimum Collectability rating; 3 Collectibles at 60k each is better than 2 Collectibles at 66k each.