Thuchan, I usually like nuts and bolts/metal washers more than threaded holes, but that depends on the particulars. These holes have no metal insert for thread: they look like they are cut into the body. That's both good in terms of coupling and contact area, and bad in terms of playing around with torque or swapping. Titanium is usually worked by taking small slices, if you catch my drift.
Although I use removable headshells, one-piece is superior IMO. No getting around the facts of 8 additional electrical connections and a physical boundary to bounce vibrations back in the wrong direction. Of course removable types have the advantage of ease of swapping, and look at all those shells you can try, to make it sing.
I have no plans to try the cart. I spend far too much time and money with this stuff as it is. Time is the most precious thing we have and most people realize this when it's too late. I'm on this thread mostly out of curiosity and felt like digging around. I had forgotten about this one below - a couple of testimonials for the protractor:
https://forum.audiogon.com/discussions/where-to-find-uni-din-protractor