If anyone's interested, these are the padlocks I bought for training: https://www.amazon.fr/dp/B07WTK8YRW
After doing a bunch of research on them when I wanted to start DD picking, these were the most often recommended or mentioned. There are numerous videos on the tube of you that go over both of these locks, including some instructional videos from Bosnian Bill and others.
I've found the first one to be VERY easy to open. I kinda opened it by accident the first time and I'm able to regularly get it open. That being said, it is the ONLY DD lock that I can seem to get open. Even after watching and trying to figure out every other DD including Kryptonite bike locks and others, I can't seem to get the feel for it. Try at your own peril:
Chinese generic: https://smile.amazon.com/gp/product/B07WTK8YRW
Zarker J45: https://smile.amazon.com/gp/product/B07RD3NTTB
So I followed your link and got a similar one to what I found previously. Fortunately it referred me to this one! https://www.amazon.ca/dp/B07WTK8YRW/
It's an < $20 starter lock so thanks!