Here’s the new updated grip and buttons on an actual TS100 (this is actually a Pro32, which is a rebranded TS100 by Sainsmart).
The buttons recess around ~0.5mm to 1mm into the case and I thought they wouldn’t work, but when I assembled the iron, I realized they just require pressure centered over the button, so they work perfectly.
You can actually hold the iron around the buttons and they won’t press unless you squeeze it very tightly.
The updated grip is pointier and the bottom is trimmed to make sure it’s flat so you can set the iron down and it doesn’t rotate easily. The pattern is a bit like knurling where it’s made to grip into your fingers to it doesn’t slip while soldering.
Edit: Renders below for slightly clearer idea of the texturing and shape:
