Nice Work!!! challenges and all!

Thanks for some great photos too...

You may have know if this already (???) I have found in recent years an old method...I guess you could call it "pseudo-hewing" (???) shared with me decades ago that seems to work well with such a species as Elm, Locust, Osage, etc...

Instead of employing an edged tool (aka axe) to create the Joggles up to the layout lines...We use a saw to kerf...sometimes closer together...sometime further apart than what you would find standard with many hewing practices...

For this type of hewing the primary tools are saws, wedges/gluts, roundel slicks/gouges, and scrub planes...A hewing axe/hatchet can be employ at certain stages and or straighter grain...

The method is extremely accurate for such species and very fast for others as well. I would also note this method also allows for more sculptural effects to be achieved like spirals, bends, etc...