Creating a double of yourself would probably best be done like a veil, because the goal is the same: you want someone to not focus on you. It is a different narrative, but mechanically, it should be pretty similar.
I would let channelers create enchanted items, but only charged with evocation effects, that they are able to create with their channeling specialization. That way, it would basically just become an item that can take casting stress for them for a number of casts. They exchange more power (focus items) for more casts, I think that is ok.
On too powerful crafters, remember, that they are still wizardly types, and they have aspects to reflect, what they are good at, and what not. Pretty much like Harry and Molly with spirit magic (raw force vs. veils).
