Thanks much! That puts things into better perspective. I've got four maybe five years of coils but at some point I'm likely to start needing to make my own. Really something I didn't want to get involved in after seeing many impedance accidents in 35 years in the audio industry.
Building your own coils is pretty Straight Forward. And with Simple precautions, it is Safe and Easy to do.
And the way things are going in the USA FDA-wise, now might be a Good Time to get Started.
WARNING: The Day I build my 1st Coil was the Last Day I Used a Coil Heads in a tank. The Improvement was that Good.
So I take No Responsibility if your try Building your own Coils and it makes your 5 Year Supply of Coil Heads Obsolete.