I forgot where Ryan mentioned it but when he was in Japan he used to practice wiring with cut off branches. I just completed the first class for Elongating Species 1 and the second class is in Oct and Ryan told us to practice our wiring. I plan to rewatch his wiring videos and practice on branches. I just ordered some aluminum wire (so I can reuse it). Might be something to try if you’ve got nothing else to do. Better screw up on branches than your trees.
Be careful with aluminum. It’s a lot softer and ruins your technique for copper. At least it does for me. I like to make sure to do some copper work when I can just to keep the skills up. Primary issue for me is that aluminum leads me to looping instead of doing the diamond shape when wrapping the wire.