Focus Coil circuits?

[mbates14]

Does anyone have any examples of Electromagnetic focus coil circuits theyd be willing to share?

I have an electrostatically focused set that I am attempting to adapt to electromagnetic focus because i got my hands on a CRT, and its NOS.

I found a Merit MF-4 coil listed on ebay, but I do not know which sets it was associated with or how to build a focus coil circuit outside of whats built-in to a normal set.

Thoughts? Thanks.