The other problem is if you measure you hand it will be different from a measurement from under your tongue core temp and surface is not the same thing. I read somewhere (I wish i could remember where so if anyone knows where core temps are please let me know) That the target core temp was about 85-7ºF but that is from memory and from an un known source.

interesting quick read but no numbers...

http://www.petplace.com/reptiles/und...ure/page1.aspx