This site provides the kind of info we need when working with toroids. It even tells you the length of wire to cut. It links to the W8DIZ “Toroid King” website, but I can’t really tell if this site is the work of DIZ himself. In any case, very useful. We award this site our coveted rating of “Five Soldering Irons.”
The “toroids.info” site does belong to Diz.
A lot of work has gone into this information. Well worth the 5 irons award.