The acknowledged "expert" on the coil waste issues of the WF series is Gregory Shoults. He has an exhibit here on Frajola's Philamercury board.
It should blow your mind..
https://www.rfrajola.com/PDR2017/Sh...Shoults3.htmHe has several other Washington Franklin exhibits there that should be required viewing for anyone interested in the subject. They can be found here. You have to scroll down as the exhibits are in alphabetical order by exhibitor.
https://www.rfrajola.com/exhibits.htmMike