The T&G ceilings are highly suspect. Run the blower door for 20 or 30 minutes and then take a look at them with your IR. If you're going to buy a blower door, my rec is to just order a new unit from Energy Conservatory. You can sometimes buy them slightly used on eBay, but the price won't be much less than new, and you won't get a new manometer that way. As far as training goes, I took BPI training but was fortunate to get it through Washington State U, rather than one of the many diploma mills out there. You could also look into the Saturn Online curriculum, and their books. What you need and can benefit from depends a lot on your experience level with construction, building science, and inspecting.