might not make sense to use tubing. The clips I've seen have been very small, like 1/8" Bending that to a tight radius seems like a chore. I don't see benders on ebay in that size very much. There is a guy that makes clips and water bottle cages at shows so there are a ton of pictures of his tooling on internet picture sites. I'd look at that for ideas. Of course, his tooling is pretty robust so he can be repeatable. You don't necessarily have to have the same level of robustness.