Jaydee I would suggest something like this (see attachment) which is what I think Bill is driving at. (?)
It is a variation on the fluxblock concept and something that Groth came up with independently a while ago. It will give you a rather accurate idea of the face temperature. Adding the "mini Fluxblock" as shown in the drawing gives the same ability that I have with the fluxblock, namely the ability to measure TIM performance. The small holes are for thermistors/thermocouples/whatever's your poison, the big ones for heater cartridges.
I would recommend a 12mm die because I am biased, that's what I have been using
I would like others to do the same for data comparison reasons