So, straight line nanako (like the video of Ford making nanako at the V&A) are enough of a problem even with etched guide lines- how do you think curved nanako would be done without guidelines? I’m sure there were nanako-shi who could do it but, imho, the smarter or less skilled would have engraved guidelines first, perhaps by scribing from the edge to the center at the proper interval. Some deeper guidelines seem to me to help create squarish nanako, but not leaving the precise distance between individual nanako can also result in squarish or pentangular nanako when seen up close. With regard to multiple nanako punches, we often see their use on furniture and armor. There is a good article on the building of Buddhist butsodon that shows a wide variety of punches used by these metal workers (sorry but this is the only information I have on my hard copies- WEB.kanagu.PDF [2006]; Section 7: The work of the decorative metal fittings artisan (kazari kanagu shi).