"Gut all" would be a good option to have, to avoid all the clicking. Also, in the Crafting tab, the number that could be made does not take into account the number of raw materials required. For example, having 2 deer leather means only 1 deer hat could be made, but 2 is listed.
Bug report: I had rabbit and moose meat that had finished tanning in the tanner, and due to lack of space in my inventory, I added some deer pelt to the tanner. The deer pelt promptly disappeared. I suspect it was because the tanner was not emptied of items that had finished tanning before more was added.