That sounds like a pretty good idea. It should work as good as oem heat shields and won't have the detrimental effect that heat wrap has on piping.
FYI, you should know that the thermal wrapping will keep the temp in the pipe hotter so that the kinetics will cause the metal to be eaten away more quickly. That is the principal reason that header makers don't warranty pipes wrapped in thermal tape. The best compromise is a heat shield between the hot item and the items you want to keep cool.
warmonger
