Before you go and grind out that level on the new tier, look up all the uses of the materials (I use GamerEscape) if your goal is sustainability. You'll also want to look into what Leves you intend to do on your crafters. Many materials, you will find, may only need a stack of 40 to never run out (Danburite for a small group of jewelery) or you may choose not to gather any at all (Maiden Artichoke is ONLY used for Stuffed Artichoke recipe).

Triple turn-ins require 3 items to complete and can be repeated two times without using another allowance. 9X the materials but 3X the EXP & Gil. So aim to gather up materials that can be used to make those items (IE Walnut Lumber and Iron Bar can both be gathered and the resulting item would be a candidate; Walnut Lumber and Iron Bar and Crab Oil requires monster drops). Leve item-rewards rotate. Aim for useful materials or large quantities of shards (about 50) to save mining time later.