Engine Temp Gauge Sensor

On my KZ1327 project, I want to put a temp gauge on it. Its a big block and we know they get warm. What I'm asking is, My ZN1100 cylinder head prepped by LarryC was threaded in the rear boss of the head at 10mm. I'm looking at Trail Tech TTO gauges. Would i get more accurate reading with their spark plug sensor or at the original sensor at the lower back side of the head?

I would put it at rear boss. But that´s me. If Kaw took temperature from that point for its EFI, good enough for me.

thanks for your imput. tom