We have the testimony of Oliver Barthel, who worked with Henry Ford at the Henry Ford Company (now Cadillac division of General Motors) and at the Dtetroit Automobile Co, another earlier venture that predates the current Ford Motor Company. Barthel was an automotive engineer who stayed close to Henry for his entire life. His reminisces are very interesting, and give a lot of insight to the serious historian when trying to capture the personalities and behind the scenes activities of Henry throughout his career.
Barthel was called in by Henry to try and fix the design flaws of the Model K. Harold Wills, of course, is the primary engineer / designer of the Model K. It is interesting to hear of what Wills looked like, and his demeanor.
Here is Barthel's story.
Link to the entire testimony: