Nice rack! (Am I allowed to even say that on here?)
Just watch out for rust developing on the spring steel. I doubt it would eat through the metal any time soon, but surface rust might get into the rope.
It's been many years since I made my own rack - or harness, pack, etc for that matter. Good to know innovation isn't completely dead when it comes to caving gear. Like Scott said, you never know where it will take you...