A topstitch needle is the same as a metallic needle. Ask Joann's if they have that.
The idea is that the thread should be as relaxed as possible. First, I tell the thread to relax :-), then I try to relax myself. You need as little friction as possible--I don't have the thread run through the guides that are just above the needle--just let it come straight down to the needle--this reduces the friction some, as does the larger eye needle.