This is the first design that is fully mine and made with something other than tinker cad. I found the included reference photo and thought it would be a good choice to start modeling.

The lock can be made with the included pins or 5 m4x20 screws and 1 m4x8 screw. you will need 2 springs that you can take from a ballpoint pen. the first spring is cut in half for the lock arms and the second is optional and always the shackle to pop open when the key is turned.

As for the print setting, supports shouldn't be needed if you have good bridging, only real recommendation is to make sure you print the key with thick walls so it's strong.