Honestly, there is no right answer, I have had success with my probe in the hot end and in the centre. I can't really say any more than was said in that thread I linked in the earlier post. Try it in the cool end if that's what your thinking, you'll probably find you may have to move it slightly anyway, you'll rarely get it spot on first time. The best thing with this is not to ask others what they think as its your setup. You understand the basics now so the only way to learn is to have a go and keep fiddling until its spot on as each viv and setup differs!