Leviathan.Frostrike said:
»You want to purchase the Tanner's Emblem to synth up a Tanners' Stall. The Tanners' Stall, the hide stretcher, and some ice weather furnishings will hopefully net you Mega Moglification: Leathercraft which is a boost to your leather crafting skill (about +5).
Or make the Tanners' Stall (and any other GP items) the only item(s) in your Mog House Floor 1, and put all other furnishings on floor 2. Floor 2 furnishings have no impact on the Mega Moglification key item you get.
Yep. Get the stall, make sure ice is your strongest energy, and you're set. Check your key items to double check if you'd like. Voila! :)
Aside from that you can get the item so you can craft multiple hides at once, it'll definitely save you tons of time!
The ring to only synthesize non-quality might also be useful, not too sure anymore aside from Tempus Fugit. Good luck!