TL:DR - I made a cool pen and you should go and buy it. If you make anything creative, you’ll probably already know that getting something right first try is pretty unusual. My experience has been that most of the work I do in a project is re-doing or refining something I didn’t get quite right in the first version. There’s value in getting an imperfect first version into existence as it gets everything in motion, and momentum is important
The blade that you made is one of my favorite drawing tools! I'm going to try to snatch one of these new pens up ASAP!