Ok, I want to know where the best place to install an aftermarket temp gauge?

I already fawked up and tryed to put one in the upper radiator hose housing (where it connects to the block) the little bleed valve, I took it out and got an adapter, and screwed it in and striped out the threads, so I had to go to the yard and get a new housing, drain my radiator, put the new housing on, let the selant dry for 7 freakin hours, and then fill it all back up and blead the system of any air.. And then I was thinking and I was wondering where the most acurate place to install this sensor would be? Befor or after the thermostat? And then I found the thermo, and I was a little lost? I am use to the thermostat being on the upper radiator hose? Why is it on the lower hose? And I wanted to know what direction the water flows through the radiator? Does it flow up? Or down?

Somone please help me out, I got all my junk in my car, and a sensor hanging in my engine bay that needs a home.