twe56,
Call the manufacturer and tell them the different locations you want to place the insulation. I have done it and gotten all sorts of answers.
I bet the JCW suggestion is for an engine compartment (and for CA/NM/AZ).
Here is the best answer: use insulation that has foil on both sides - you can't go wrong as to which side goes in which direction in which part of your vehicle in which part of the country in which part of the year.
The hot/heated side is not a very helpful guideline but it seems to be the answer most often given.
Tim
This is a picture of
ceiling insulation in my Suburban.
Below is a photo of the ceiling from another suggestion.
[img]http://ares.cs.siena.edu/~lederman/truck/Photos/Reassembly/ceilinsul1.jpg[/img]
