DC300 Coming from the manufacturing (and measurement) world, I know about tolerances, but I guess I'm surprised that heads, or most anything else, could still be so far off in some cases. It's 2020 and we have a LOT of technology that should ensure at least relatively tight tolerances.
This is at least partly why I always loved getting the handpicked Wishon heads. I had the fitter check a # of driver heads, including a few Wishons, and he noticed the Wishons were all very nearly square and 11*. I told him I had those handpicked that way and he was a bit surprised I got what I asked for lol.