Would't a TVS be useful?

TVS is the answer to my question, yes. Even though I didn't explain everything well. If I was to post again I'd simply state that I want to push the FETs to their limits so I can get the most out of the coils. I think that screams TVS now that I understand them.

 

I remember now why I wrote what I did to your "current in an inductor at supply switch off does not change". Because that's not at all true. The issue is one of magnitudes ...

At the coil, there is an abrupt change to the rate of change of current. Before cutoff there is a relatively steady state where rate of change of current is zero. That means zero electric field created due the the current. At cutoff right at the coil you can easily see the discharge curve showing the abrupt rate of change of current. Electric field created by the current in the coil goes from zero to some value almost immediately. This is the effect I mentioned earlier. It's very real, but it's nothing in comparison to the rate of change of current at the drains during cutoff.