Here is a prototype rig that performed well on its maiden flight. The design might be appropriate for matched visible/IR cameras for vertical photography, like the Canon A495s from the Balloon Mapping Kickstarter project. For such a use, it would require the addition of an intervalometer to trigger both cameras simultaneously. I am not yet sure how to add that function.
I aligned 15 photos from the test flight in MapKnitter, just because it's fun to use MapKnitter. https://mapknitter.org/tms/lone-rock-pond/openlayers.html