Not sure how much prior experience you have cooking. However, based on really bad coke purity in many areas these days, the reason you might be struggling is you’re trying to make hard out of a lot of non-coke.
I’m a pretty good cook of the stuff, and what I’m seeing across different starting powder batches these days is hard that ends up grainy and wet, hard that seems to take forever to set, and hard which sets way too fast and solid. In every case, that is pointing to impurities in the coke itself. Different ones produce different cooking reactions.
I notice you never followed back up on your original question, but I’ll gladly answer any questions you have if you return.