That is awesome to hear that you guys cloned it! I've yet to try that with a champion type tree, but have done other simple experimental clones with Red Maples.
I have a Black Walnut I am doing some work on this spring in Wisconsin, the largest I have ever seen! It is a victim of a lightning strike from over a decade ago. Low co-dom with a 50" DBH trunk, split(the co-doms are massive) from the strike.
The interior wood around the split is in good shape, almost no decay, and wound wood/compartmentalization is doing well. Going to install a static cable and prune major deadwood. Hopefully it sees at least another few decades of good livin'.