I just posted the finishing pass for this terrain and got a whopping ~900k lines. I feel like early on there was an issue with memory allocation, but I believe that has been resolved, right?
surprised nobody replied to this… yes when you update to 1.0.8 it expands storage to fill the sd card in the controllers RPi. This should allow you to do GB sized files. That said, not sure how it will performance at 900K lines. I have never done it. It should be ok I would assume but due to duration of that carve i would definitely keep different tools in their own files so you can easily compartmentalize the work.
I loaded and ran 1.68 million lines the other night. It took about 15 minutes to load the file into the controller, but ran fine start to finish.