The 4060s were in a croakie, I was seated near the tail of the piano front row. The stage was raised, so I would estimate I was about 8 feet away out from the end of the piano and slightly below (maybe 1-2 feet) the top of the tail . The room was not a concert room but had small tables in a boxy (but largish) room (but good views of the city).
The Rode app has a settings page to choose sample rate and mono/stereo. With the d:vice attached, you are offered up to 96kHz, but with just the iPhone mic you're offered only up to 48kHz. As I said, when the recording is ended, you are offered formats for saving it, if it runs over 4GB it only offers CAF for uncompressed. Shorter files can be saved as WAV. I am avoiding touching the two ways to set levels in Rode Recording because it can, under some circumstances, change the d:vice levels. My settings were low to be conservative until I get a better feel for the gear, and I boosted by 8dB in post.
Jeff