There will be an attach point system in 2.1 which could work quite well for this. More details here:
https://trello.com/b/UfqlXqXy
Even with this system, it seems my workflow needs to be to have all images made exactly the same with my artist making the "bind point" of all artwork be in the dead center of the image.. that or set a custom anchor on every single image itself in tk2d. The former method seems a lot easier, but that's a lot of hassle having to create artwork not "equipped" to the model which I understand.. but can be worked around by creating a separate layer with a human head on it in the middle of the screen while working on helmets, etc....
I guess the question is... what's the correct way to use the toolkit if I have 100 helmets, 100 shirts, etc. Right now it's export in PS at full 40x40, put child GO's on my sprites for equipment points, manually set a weapon in the scene and record the vector3 position of what looks right and for that Race like Ogre, Human, Halfling etc set the "mainhand" vector3 and know to move the sprite to that location. If I did a custom anchor on every single image then all I would have to do is set the sprite.position to the mainhand.position of each Race, but that is a lot more overhead when importing all 500+ images into the game.
Another workflow is to make a sprite collection per equipment slot but that's a draw call each if i do that, resulting in like 10 DCs just for players and this is targeting mobile. I only suggest that because I notice you can shift click all and set bind points for the entire sprite collection instantly like that (great feature).