The larger the tip/shaft diameter and the greater the included angle the more robust the scribe. Even the heavy duty shaft diamond point tools are meant for scribing light lines for marking or scoring for breaking. They are not meant for engraving or machining.
The most robust diamond scribe is with a 90 degree included angle giving the diamond a 1mm base width. It is suitable for students and the general public. It has been purchased for scribing wedding bowls and silver trays by guests.
For scribing to break the Deluxe Diamond Scribing Pen is ideal for a production environment where many people may be using the tool. It is more tolerant of untrained personnel who might over apply pressure that would break a more delicate tip.
For personal use a more delicate scribe with a finer tip but a sturdy shaft and broad base (90° included angle) would be depending on the scribe head angle desired. Next would be a 60° angle for very delicate scribe to mark or break. Breaking of flat substrates is best facilitated using Wafer Cleaving/Glass Breaking Pliers.
The Fine Point Scribes and Micro Tool Scribes are for very delicate scribing like marking identification on the back of a Silicon wafer or glass slide. We don't recommend these for scribe to break applications where a deeper scribe mark may be required.
That stated, we can't guarantee that a specific scribe will be suitable for varied applications.