I did my 66 with Fatmat
http://www.fatmat.com after lots of research. They have different products depending on what you want and they are cheaper than Dynamat.
I really love the stuff in the doors: makes the ride feel and sound "solid". Not sure what it does to reflect heat but that wasn't my concern in Wisconsin.
As to removal, wear gloves or you will need sutures!!! Can be removed though.