with the tubes ID of 0.055" i would try 0.165" (4mm) cups and the tubes are 0.276" (6mm) above the cup base.
cupOD = tube Id*3
Tube height = tubeID*5
when i have time this is what i am going to try next a using a 10mm copper base.
your spot on with 19 cups / tubes.
until you get the balance correct your will results will stay the same as the maze4, then they should drop by 3-4C but thats from my experiance making this type of block. Shame i never get to see the drop though.
would you like to try the joystick temp reading software i have ? you can calibrate it with your thermocouple and then just leave it recording on a second pc.
http://homepage.ntlworld.com/lee_smith/joystick.zip
instructions for making the joystick port reader here
http://www.benchtest.com/gp_Temp4.html