ut it seems that you simply ignore the test quoted above anyway.
and so you ignore the test in post#1?

Why did he get very low temperatures with direct touch? Think Frank should offer a few screenshots and pics from the hole setting...
This is no easy topic. Somewhere, there have to be a maximum of cooling performance with water. The more surface the better temps? Perhaps the minimum of copper compared with the most posible surface is the solution, don't know.