Actually, if you are open minded, you will realize that making anything is way more complex and subtle than you may realize. Everything you do to something changes the sound. The foil purity, the foil direction, the foil thickness, the wax, the paper, the heat applied, the tension of the winding machine, the curing, the bobbin in the center, the direction of winding, etc. all contribute to the final sound. I tried the 12 gauge wax paper Jensen coils and they suck big time. I hope your custom Erse ones are better than the Jantzens.......but there is really absolutely no way to know what the final result will be till you listen.......and if it is not as good as the Jantzen, then what was the thing/things that did not allow the best sound?.....you might have to try many, many versions to arrive at something worthwhile.
Jupiter copper foil development: "Every aspect of the capacitor construction was evaluated during the 4 year development process. Even the smallest details were addressed which resulted in significant improvements in sonic performance. Wax with very special sonic characteristics, better damping and thermal characteristics was chosen as a perfect match. Further, new lead termination technique has allowed the music to flow more naturally. Without exception, every detail has been tailored to this specific copper capacitor design."
Years ago my friend Phil wanted to have some custom polystyrene 1uf 100V caps made (for use in modifying Acoustat electrostats). He was working for Sumiko at the time and Sumiko had access to really good tin foil. So, Phil sent this foil off to 4 different cap manufacturers along with some Mogami wire to use as leads and his own favorite solder. So all the various capacitor winding companies had to do was add their own polystyrene (some say all came from one factory in Germany) and wind them and solder the leads on using the same solder and wires.....well, guess what?......they all sounded different.
One thing is for certain: Your custom Erse wax coils will not sound like the Jantzen wax coils. Which one wlll be more transparent? No one has any idea....no one.
Meanwhile, we can all get a fantastic upgrade by getting Jantzen Wax foil coils.....they are simply amazing.