The male fast clip part must be printed horizontally, FDM printed parts are always weaker in vertical axis due to layer adhesion issue. It also should be printed in ABS because of its flexibility. PLA cannot bend.
If you'll use it with more extreme sports I strongly recommend acetone finishing to make the ABS part stronger.
This design is very similar to the original, witch was designed to be injected in a high quality engineered plastic. If there is demand for it to be printed I'll redesign it having 3D printing in mind. So post your prints and videos!