I have not tried plugging it in while wearing it, I don't know if the GPIO pins will shock you. Wearing the device over a sleeve, or putting something underneath it, might reduce that risk.
The case must be printed in a solid filament like PLA or ABS. Every other part should be printed with a flexible filament like TPU/Ninjaflex.
There are 2 different strap lengths, the CUSTOM-LONG-STRAP and Strap a. I would suggest trying the longer strap first, and if it does not fit then try the smaller one.
Be careful pushing your Pi into the case, it's a tight fit! You may have to use a small flat-head screwdriver to pop the case over the data and power ports of the Zero. The good thing is, there is no risk of the Pi falling out of the case :)
How To Put Together
This was a pain to make. I had over 50 iterations and I think 4-5 final prints before I got it just right.