I think the black tiles you're seeing are the actual mesh tiles. It seems that the orthophotos haven't been picked up from the LINZ server, and you're just left with a blank canvas.
Have you tried using other ortho sources (such as GE2 - which is very high quality) and then selected some small areas on the map to render? My suggestion is to not go overboard, and just do little tests at a time to fine-tune your skills...
I agree that it's a convoluted exercise to get everything to work (dealing with Python scripts and terminal commands was seriously daunting to start with, but I got there in the end...), but once it is set up and running correctly, the results are amazing!
PM me if you're still having problems, and I'll see what I can do to help...