the 1/2" NTP will be way to small for a heating element.
use one for the valve, one for a thermometer, and one for a site gauge.
Your going to have to punch a 1 1/4" hole in your pot for the element.
I put mine in by offsetting it slightly from the sight gauge. I assume you mean your going to mount it horizontally.
here is a good example of it.
http://www.theelectricbrewery.com/heating-elements