Ed,
I've not done it, but I have seen various trucks, ambulances and especially
furniture dealer trucks heavily clad with decals of all sort being done.
What I saw was men with heat guns pulling small and even hugh decals from
sides, tops, fronts, and backs of just about everything. They seemed to get
started on one edge, then heat and simultaneously pull so as to never
actually heat beyond just what it took to release the decals. They were
using what looked like white nylon or plastic scrapers to get started. Seems
to me that would help you to avoid any overheating durning the process. On
the older vehicles the decal so protected the underlayment that the script
and or block of decals was quite apparent when finished and a large new
block of paint or the actual script of the decal was sort of still there in
the form of "new" paint exposed. That may present a problem for you too.
Why don't you investigate your area for those business who apply decals. I'd
bet they also remove them and might give you some free pointers you may find
useful.
-Eddie- Houston