[rcheshire (Rowland)]

Here is an exiftool dump of one of a series of images taken at -5C cold finger temp. Given that frost will form on the sensor face if not protected, 12C exif bares no relation to the temperature of the CMOS, or the associated electronics on the backing PCB.

In real terms exif is of no practical value to the DSLR cooling mod. The file is one of 200 bias frames taken in one sitting to produce a superbias.

EDIT: Despite using the same cold finger pattern for several years I think cutting a large swathe out of the middle section might improve performance, as long as there is adequate metal for a cooling pathway to the sensor tongue.