Thus far, inking the Dürer copy has been successful but slow. I had some trouble at first with Dürer's mark due to the angle of the pen. Whenever I was trying to make a mark that was thicker or heavier at the top, the pen would catch due to the curve of his mark. In some of the pictures below you can see some of my practice.
Probably the hardest part of this process is honestly just looking at the lines and figuring out where each line goes. There's such a high density of lines overlapping, especially in the part I worked on between the 4th and the 6th, and just seeing where they go is quite a challenge.
Initially, I had been penciling in most lines as I went to make sure I got the proportions just right, but because that took such an excessive amount of time, I've moved away from that and have tried to just freehand most of the smaller, less important lines. It can be more frustrating because mistakes are permanent, but because there are so many of the lines, no mistakes will really stand out unless you compare the drawings at each line. However, I am very proud of the work I've done. Every single line (except one that I forgot and there isn't room to add it in) is in place, and overlapping with the same lines in the same places as the original.
One more frustration of this project is the scale. This piece is massively bigger than the original, which is only 8.2 inches by 5.8 inches, so the width of the pen relative to the paper was much larger for Dürer. This essentially means that on my copy, there is much more white space relative to inked space because the pen is so thin. I've tried to fix this by going over lines multiple times to make them thicker, but it's still not quite right, and it changes the effect somewhat.