Thanks for your support
For the hot regulator problem, right I now I am using a 9V DC supply to power the board. VT1 is not soldered yet as I have not using that to power the TEC. I am in early stage, TEC is testing with a stand alone DC power.
I have understand your description of the "T" colder finger. I have also see some similar designs from CN forum, see below pictures. I will use design 1 to make the TEC outside of the case and also a "T cold finger