I checked out the brass 3/32" rods they had at hobby lobby - might be a little too malleable for the coil gizmo application, but maybe not.
I was too cheap to throw another $4 bucks at it so I used my drill bit kit for my dremmel to rebuild my chicas vivi nova heads. Holy crap that thing is tricky to rebuild! The pro tanks are a breeze compared to those.
My fingers hurt a good bit now, but I think I may just stick to the drill bit approach instead of the coil winder. With a good pair of tweezers and a little pen torch (man that thing is fun to play with!), I've been getting my wraps pretty tight!