I'm planning to watch these videos on weekend. As I'm just about to start this business

I'm already in the printing industry for a while now. I do agree with the Tips you provided. That's so nice of you to take your time out and share your knowledge with the noobs.

You should try to skip the concave first. If it works better you may know what problem you are facing with the printing. Or you may try to print it to a simple wood piece.